Rats Archives - Revista Brasileira de Ginecologia e Obstetrícia
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2015;37(5):233-240
DOI 10.1590/SO100-720320150005333
To assess the effect of tibolone on mammary tissue of castrated rats over 3
different periods of time.
Sixty virgin female Wistar rats were submitted to oophorectomy. Twenty-one days
after surgery, with hypoestrogenism confirmed, the experimental rats were randomly
assigned to six groups: Tibolone 1 (n=10) received tibolone 1 mg/day for 23 days,
tibolone 2 (n=10) for 59 days and tibolone 3 (n=10) for 118 days. The groups
control 1 (n=8), control 2 (n=7) and control 2 (n=10) received distilled water for
23, 59 and 118 days, respectively. After treatment, all six pairs of mammary
glands were removed and stained with hematoxylin and eosin (HE) for histological
analysis after euthanasia. The histological parameters evaluated were: epithelial
cell proliferation and secretory activity. The variables were analyzed
statistically, with the level of significance set at 0.05.
Histological changes were observed in 20/55 rats, mild epithelial hyperplasia in
7/55, moderate epithelial hyperplasia in 5/55, alveolar-nodular hyperplasia in
7/55, atypia without epithelial proliferation in 1/55, and no cases of severe
epithelial hyperplasia were found. Secretory activity was observed in 31/55 rats.
The secretory activity was significantly higher in the tibolone groups compared to
control at all the time points assessed (p=0,001). The histological changes were
did not show significance when the control and tibolone groups were compared. The
time of exposure to tibolone did not show significance when the three different
periods of evaluation were compared.
No relation between histological modification and tibolone treatment was verified
after short-, medium- and long-term treatment.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2015;37(5):233-240
DOI 10.1590/SO100-720320150005333
To assess the effect of tibolone on mammary tissue of castrated rats over 3
different periods of time.
Sixty virgin female Wistar rats were submitted to oophorectomy. Twenty-one days
after surgery, with hypoestrogenism confirmed, the experimental rats were randomly
assigned to six groups: Tibolone 1 (n=10) received tibolone 1 mg/day for 23 days,
tibolone 2 (n=10) for 59 days and tibolone 3 (n=10) for 118 days. The groups
control 1 (n=8), control 2 (n=7) and control 2 (n=10) received distilled water for
23, 59 and 118 days, respectively. After treatment, all six pairs of mammary
glands were removed and stained with hematoxylin and eosin (HE) for histological
analysis after euthanasia. The histological parameters evaluated were: epithelial
cell proliferation and secretory activity. The variables were analyzed
statistically, with the level of significance set at 0.05.
Histological changes were observed in 20/55 rats, mild epithelial hyperplasia in
7/55, moderate epithelial hyperplasia in 5/55, alveolar-nodular hyperplasia in
7/55, atypia without epithelial proliferation in 1/55, and no cases of severe
epithelial hyperplasia were found. Secretory activity was observed in 31/55 rats.
The secretory activity was significantly higher in the tibolone groups compared to
control at all the time points assessed (p=0,001). The histological changes were
did not show significance when the control and tibolone groups were compared. The
time of exposure to tibolone did not show significance when the three different
periods of evaluation were compared.
No relation between histological modification and tibolone treatment was verified
after short-, medium- and long-term treatment.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2014;36(5):233-233
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2014;36(5):233-233
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2013;35(4):159-163
DOI 10.1590/S0100-72032013000400005
PURPOSE: To evaluate the effects of electrical stimulation (ES) of the pelvic floor on the urethra of female rats. METHODS: Forty adult rats were divided at random into four groups of ten animals each: Ctrl - without intervention; Sham - not submitted to ES, but with an electrode inserted into the vagina; Exp6 - submitted to six sessions of ES of the pelvic floor, and Exp12 - submitted to 12 sessions of ES of the pelvic floor. At the end of the experiment, all animals were anesthetized and the middle third of the urethra was removed, fixed in Bouin's fluid and processed for histomorphometric study. Sections were stained with hematoxylin and eosin for morphological and morphometric description, and others were stained with picrosirius red for the quantitation of total collagen. The thicknesses of the muscle layer and of the epithelium were determined, in 4 quadrants of the urethra, by performing 20 measurements per animal. The number of blood vessels present in the lamina propria was counted in the four quadrants over an area of 10³ µm² per quadrant and the images were obtained using the image analysis program AxioVision® REL 4.3 (Carl Zeiss). The collagen and muscle fiber ratios in the urethrae were calculated from two images per quadrant of every slice stained with picrosirius red, employing the Imagelab® Program. Data were subjected to analysis of variance (ANOVA) and the Tukey-Kramer multiple comparison test (p<0.05). RESULTS: The morphometry of the collagen, number of blood vessels and thickness of the epithelium showed no significant changes; however, the thickness of the periurethral muscle tissue increased significantly in Exp12 group, compared to the other groups (Exp12*>Exp6==Ctrl==Sham; *p<0.05). CONCLUSION: Prolonged functional electric stimulation of the pelvic floor induced an increase in periurethral muscle thickness in rats.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2013;35(4):159-163
DOI 10.1590/S0100-72032013000400005
PURPOSE: To evaluate the effects of electrical stimulation (ES) of the pelvic floor on the urethra of female rats. METHODS: Forty adult rats were divided at random into four groups of ten animals each: Ctrl - without intervention; Sham - not submitted to ES, but with an electrode inserted into the vagina; Exp6 - submitted to six sessions of ES of the pelvic floor, and Exp12 - submitted to 12 sessions of ES of the pelvic floor. At the end of the experiment, all animals were anesthetized and the middle third of the urethra was removed, fixed in Bouin's fluid and processed for histomorphometric study. Sections were stained with hematoxylin and eosin for morphological and morphometric description, and others were stained with picrosirius red for the quantitation of total collagen. The thicknesses of the muscle layer and of the epithelium were determined, in 4 quadrants of the urethra, by performing 20 measurements per animal. The number of blood vessels present in the lamina propria was counted in the four quadrants over an area of 10³ µm² per quadrant and the images were obtained using the image analysis program AxioVision® REL 4.3 (Carl Zeiss). The collagen and muscle fiber ratios in the urethrae were calculated from two images per quadrant of every slice stained with picrosirius red, employing the Imagelab® Program. Data were subjected to analysis of variance (ANOVA) and the Tukey-Kramer multiple comparison test (p<0.05). RESULTS: The morphometry of the collagen, number of blood vessels and thickness of the epithelium showed no significant changes; however, the thickness of the periurethral muscle tissue increased significantly in Exp12 group, compared to the other groups (Exp12*>Exp6==Ctrl==Sham; *p<0.05). CONCLUSION: Prolonged functional electric stimulation of the pelvic floor induced an increase in periurethral muscle thickness in rats.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2012;34(10):447-452
DOI 10.1590/S0100-72032012001000003
PURPOSES: To evaluate the histomorphometry of cardiomyocytes and collagen present in the myocardium of rats treated with a concentrated extract of soy or 17β-estradiol (E2). METHODS: Twenty-eight rats were divided into four groups: GCtrl - estrus phase; GOvx - ovariectomized (Ovx) and receiving vehicle; GIso - Ovx and treated with soy extract (150 mg/kg per day); GE2 - Ovx and treated with E2 (10 µg/kg per day). The drugs and vehicle (0.2 mL propylene glycol) were administered for 30 consecutive days after ovariectomy. On the last day the animals were anesthetized, the hearts removed, submerged in 10% formaldehyde and fragments of the ventricles underwent histological procedures, and the sections were stained with hematoxylin and eosin or picrosirius-red. Histomorphometric analysis (number and volume of nuclei and quantification of collagen) was performed under a light microscope with AxioVision Rel. 4.2 software, and collagen fibers were quantified using IMAGELAB-2000 software. Data were submitted to ANOVA followed by the Tukey test (p<0.05). RESULTS: We observed a higher number of cardiomyocyte nuclei in animals of the Ovx and Iso groups than in GE2 and GCtrl animals (GOvx=121.7±20.2=GIso=92.8±15.4>GE2=70.5±14,8=GCtrl=66.3±9.6; p <0.05), while the nuclear volume was greater in the Ctrl and E2 groups (GE2=35.7±4.8 GCtrl=29.9±3.6=>GIso=26.5±4.5=GOvx=22.4±2.9; p <0.05). Collagen concentration was higher in the Ovx group (GOvx=5.4±0.1>GCtrl=4.0±0.1=GIso=4.4±0.08=GE2=4.3±0.5; p <0.05). CONCLUSIONS: Estrogen may prevent the reduction of the nuclear volume of cardiomyocytes and collagen deposition between heart muscle fibers, while the administration of isoflavones only prevents the deposition of collagen, which can preserve the mechanical properties of cardiac fibers.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2012;34(10):447-452
DOI 10.1590/S0100-72032012001000003
PURPOSES: To evaluate the histomorphometry of cardiomyocytes and collagen present in the myocardium of rats treated with a concentrated extract of soy or 17β-estradiol (E2). METHODS: Twenty-eight rats were divided into four groups: GCtrl - estrus phase; GOvx - ovariectomized (Ovx) and receiving vehicle; GIso - Ovx and treated with soy extract (150 mg/kg per day); GE2 - Ovx and treated with E2 (10 µg/kg per day). The drugs and vehicle (0.2 mL propylene glycol) were administered for 30 consecutive days after ovariectomy. On the last day the animals were anesthetized, the hearts removed, submerged in 10% formaldehyde and fragments of the ventricles underwent histological procedures, and the sections were stained with hematoxylin and eosin or picrosirius-red. Histomorphometric analysis (number and volume of nuclei and quantification of collagen) was performed under a light microscope with AxioVision Rel. 4.2 software, and collagen fibers were quantified using IMAGELAB-2000 software. Data were submitted to ANOVA followed by the Tukey test (p<0.05). RESULTS: We observed a higher number of cardiomyocyte nuclei in animals of the Ovx and Iso groups than in GE2 and GCtrl animals (GOvx=121.7±20.2=GIso=92.8±15.4>GE2=70.5±14,8=GCtrl=66.3±9.6; p <0.05), while the nuclear volume was greater in the Ctrl and E2 groups (GE2=35.7±4.8 GCtrl=29.9±3.6=>GIso=26.5±4.5=GOvx=22.4±2.9; p <0.05). Collagen concentration was higher in the Ovx group (GOvx=5.4±0.1>GCtrl=4.0±0.1=GIso=4.4±0.08=GE2=4.3±0.5; p <0.05). CONCLUSIONS: Estrogen may prevent the reduction of the nuclear volume of cardiomyocytes and collagen deposition between heart muscle fibers, while the administration of isoflavones only prevents the deposition of collagen, which can preserve the mechanical properties of cardiac fibers.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2012;34(7):323-328
DOI 10.1590/S0100-72032012000700006
PURPOSES: To evaluate the histomorphometry of ovarian interstitial cells, as well as the blood sex steroid concentrations of female rats with polycystic ovaries induced by continuous light. METHODS: Twenty female rats were divided into two groups: Control Group - in the estrous phase (CtrlG), and a group of rats with polycystic ovaries induced by continuous illumination (POG). CtrlG animals were maintained on a light period from 07:00 a.m. to 07:00 p.m., and POG animals with continuous illumination (400 Lux) for 60 days. After this period all animals were anesthetized and blood was collected for the determination of serum estradiol (E2), progesterone (P4), and testosterone (T), followed by removal of the ovaries that were fixed in 10% formalin and processed for paraffin embedding. Five-µm histological sections were stained with hematoxylin and eosin and used for histomorphometric analysis. Morphological analyses, cyst count, determination of concentration and of the nuclear volume of interstitial cells were performed with the aid of a light microscope adapted to a high resolution camera (AxioCam), whose images were transmitted to and analyzed by the computer using AxioVision Rel 4.8 software (Carl Zeiss). Data were analyzed statistically by the Student's t-test (p<0.05). RESULTS: Morphological analysis showed the presence of ovarian cysts in POG animals and corpora lutea in CtrlG animals, as well as evidence of the origin of interstitial cells from the internal theca of these cysts. POG animals presented increased serum estradiol levels (pg/mL) compared to CtrlG animals (POG=124.9±4.2>CtrlG=73.2±6.5, p<0.05), the same occurring with testosterone levels (pg/mL) (POG=116.9±4.6>CtrlG=80.6±3.9, p<0.05). However, progesterone levels (ng/mL) were higher in CtrlG than in POG animals (CtrlG=16.3±2.0>POG=4.2±1.5, p<0.05). Morphometry showed a significant increase in nuclear volume in POG animals (POG=102.1±5.2>CtrlG=63.6±16.5, p<0.05), as well as in the area occupied (%) by interstitial cells (POG=24.4±6.9>CtrlG=6.9±3.2, p<0.05) compared to CtrlG animals. CONCLUSION: The interstitial cells of the rat polycystic ovary probably originate from ovarian cysts due to the degeneration of granulosa cells and differentiation of the internal theca cells. The elevations of serum testosterone and estradiol were probably due to the significant increase in cell activity and in the area occupied by interstitial cells.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2012;34(7):323-328
DOI 10.1590/S0100-72032012000700006
PURPOSES: To evaluate the histomorphometry of ovarian interstitial cells, as well as the blood sex steroid concentrations of female rats with polycystic ovaries induced by continuous light. METHODS: Twenty female rats were divided into two groups: Control Group - in the estrous phase (CtrlG), and a group of rats with polycystic ovaries induced by continuous illumination (POG). CtrlG animals were maintained on a light period from 07:00 a.m. to 07:00 p.m., and POG animals with continuous illumination (400 Lux) for 60 days. After this period all animals were anesthetized and blood was collected for the determination of serum estradiol (E2), progesterone (P4), and testosterone (T), followed by removal of the ovaries that were fixed in 10% formalin and processed for paraffin embedding. Five-µm histological sections were stained with hematoxylin and eosin and used for histomorphometric analysis. Morphological analyses, cyst count, determination of concentration and of the nuclear volume of interstitial cells were performed with the aid of a light microscope adapted to a high resolution camera (AxioCam), whose images were transmitted to and analyzed by the computer using AxioVision Rel 4.8 software (Carl Zeiss). Data were analyzed statistically by the Student's t-test (p<0.05). RESULTS: Morphological analysis showed the presence of ovarian cysts in POG animals and corpora lutea in CtrlG animals, as well as evidence of the origin of interstitial cells from the internal theca of these cysts. POG animals presented increased serum estradiol levels (pg/mL) compared to CtrlG animals (POG=124.9±4.2>CtrlG=73.2±6.5, p<0.05), the same occurring with testosterone levels (pg/mL) (POG=116.9±4.6>CtrlG=80.6±3.9, p<0.05). However, progesterone levels (ng/mL) were higher in CtrlG than in POG animals (CtrlG=16.3±2.0>POG=4.2±1.5, p<0.05). Morphometry showed a significant increase in nuclear volume in POG animals (POG=102.1±5.2>CtrlG=63.6±16.5, p<0.05), as well as in the area occupied (%) by interstitial cells (POG=24.4±6.9>CtrlG=6.9±3.2, p<0.05) compared to CtrlG animals. CONCLUSION: The interstitial cells of the rat polycystic ovary probably originate from ovarian cysts due to the degeneration of granulosa cells and differentiation of the internal theca cells. The elevations of serum testosterone and estradiol were probably due to the significant increase in cell activity and in the area occupied by interstitial cells.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2012;34(1):22-27
DOI 10.1590/S0100-72032012000100005
PURPOSE: Evaluate the effects of ipriflavone during fetogenesis, since no studies have been conducted to assess its effect during this period. METHODS: 60 pregnant rats were divided randomly into four groups (n=15). G-control (1 mL of distilled water) and three groups treated intragastrically with ipriflavone from the 16th to the 20th post coitus (PC) day: G-300 (300 mg/kg), G-1,500 (1,500 mg/kg) and G-3,000 (3,000 mg/kg). The animals were weighed, anaesthetized intraperitoneally with xylazine and ketamine at doses of 180 mg/kg and 10 mg/kg, respectively, and sacrificed by total exsanguination on the 21st day. A complete blood count was performed and serum cholesterol, triglycerides, AST, ALT, urea, creatinine, and glucose were determined in pregnant rats. After laparotomy, the liver, kidneys, adrenals, spleen and ovaries were removed and weighed; fetuses and placentas were also weighed to obtain the average weight of the litters. Four fetuses (two males and two females) were chosen at random for the determination of the length and weight of brain, liver, kidneys and lungs. Statistical analysis: ANOVA followed by Dunnett's test. For raw data without normal distribution and homoscedasticity, we used the Kruskal-Wallis test followed by the Mann-Whitney test. Proportions were analyzed by the χ² test (p<0.05). RESULTS: Triglyceride levels (mg/dL) were: Control-G (138.8±21.8), G-300 (211.2±63.9) G-1,500 (251.5±65.2) G-3,000 (217.7±49.6); p<0.05. The body weight of fetuses (g) was: G-Control (male 3.3±0.3; female 3.1±0.3), G-300 (male 3.4±0.2; female 3.1±0.4), G-1,500 (male 3.5±0.3; female 3.2±0.3), G-3,000 (male 3.4±0.5; female 3.1±0.4). CONCLUSION: Ipriflavone did not cause maternal toxicity, but increased triglyceride levels and reduced hematocrit at higher doses. The body and organ weights of the fetuses did not change with dam treatment. There were no external malformations or fetal deaths.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2012;34(1):22-27
DOI 10.1590/S0100-72032012000100005
PURPOSE: Evaluate the effects of ipriflavone during fetogenesis, since no studies have been conducted to assess its effect during this period. METHODS: 60 pregnant rats were divided randomly into four groups (n=15). G-control (1 mL of distilled water) and three groups treated intragastrically with ipriflavone from the 16th to the 20th post coitus (PC) day: G-300 (300 mg/kg), G-1,500 (1,500 mg/kg) and G-3,000 (3,000 mg/kg). The animals were weighed, anaesthetized intraperitoneally with xylazine and ketamine at doses of 180 mg/kg and 10 mg/kg, respectively, and sacrificed by total exsanguination on the 21st day. A complete blood count was performed and serum cholesterol, triglycerides, AST, ALT, urea, creatinine, and glucose were determined in pregnant rats. After laparotomy, the liver, kidneys, adrenals, spleen and ovaries were removed and weighed; fetuses and placentas were also weighed to obtain the average weight of the litters. Four fetuses (two males and two females) were chosen at random for the determination of the length and weight of brain, liver, kidneys and lungs. Statistical analysis: ANOVA followed by Dunnett's test. For raw data without normal distribution and homoscedasticity, we used the Kruskal-Wallis test followed by the Mann-Whitney test. Proportions were analyzed by the χ² test (p<0.05). RESULTS: Triglyceride levels (mg/dL) were: Control-G (138.8±21.8), G-300 (211.2±63.9) G-1,500 (251.5±65.2) G-3,000 (217.7±49.6); p<0.05. The body weight of fetuses (g) was: G-Control (male 3.3±0.3; female 3.1±0.3), G-300 (male 3.4±0.2; female 3.1±0.4), G-1,500 (male 3.5±0.3; female 3.2±0.3), G-3,000 (male 3.4±0.5; female 3.1±0.4). CONCLUSION: Ipriflavone did not cause maternal toxicity, but increased triglyceride levels and reduced hematocrit at higher doses. The body and organ weights of the fetuses did not change with dam treatment. There were no external malformations or fetal deaths.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2011;33(9):264-269
DOI 10.1590/S0100-72032011000900008
PURPOSE: to evaluate the effects of high doses of genistein on the mammary glands of adult female rats. METHODS: Twenty-eight days after oophorectomy, 50 adult female rats were divided into five groups, as follows: a control group (Ctrl), three rats that received genistein (GEN) at the doses of 46 mg/kg (GEN46;), 125 mg/kg (GEN125) and 250 mg/kg (GEN250); one group received conjugated equine estrogen at the dose of 50 µg/g (ECE50). The substances were administered daily for 30 consecutive days by gavage and in the last week of the period of treatment, colpocytological exams were carried out for seven consecutive days. After treatment, the animals were anesthetized, blood samples were collected for estradiol and progesterone determination and the first pair of inguinal mammary glands was removed and processed for histomorphometric analysis. Collected data were subjected to analysis of variance supplemented by the Tukey-Kramer test (p<0.05). RESULTS: the ctrl group and the ones treated with different doses of GEN showed atrophic mammary glands, whereas the glands were more developed in the ECE group, where numerous mammary ducts and alveoli were observed. Morphometry showed a larger area of mammary parenchyma in the ECE group (98.870.1±550.4 µm²* per mm²; p<0.05) compared with other groups (Ctrl=36.875.6±443.4; GEN46=37.001.7±557.4; GEN125=36.480.8±658.3 and GEN250=37.502.8±669.3). The same occurred in the number of alveoli in the ECE group (33.2±6.9* per mm²; p<0.05) compared to the other groups (Ctrl=10.4±2.1, GEN46=11.2±3.1; GEN125=11.6±2.1 and GEN250=12.3±2.3). The estradiol level was higher in the ECE group compared to the other groups (9.4±1.7 pg/mL; p<0.05), whereas serum levels of progesterone were similar in all groups. CONCLUSION: the administration of genistein at high doses had no trophic effect on the mammary glands of rats.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2011;33(9):264-269
DOI 10.1590/S0100-72032011000900008
PURPOSE: to evaluate the effects of high doses of genistein on the mammary glands of adult female rats. METHODS: Twenty-eight days after oophorectomy, 50 adult female rats were divided into five groups, as follows: a control group (Ctrl), three rats that received genistein (GEN) at the doses of 46 mg/kg (GEN46;), 125 mg/kg (GEN125) and 250 mg/kg (GEN250); one group received conjugated equine estrogen at the dose of 50 µg/g (ECE50). The substances were administered daily for 30 consecutive days by gavage and in the last week of the period of treatment, colpocytological exams were carried out for seven consecutive days. After treatment, the animals were anesthetized, blood samples were collected for estradiol and progesterone determination and the first pair of inguinal mammary glands was removed and processed for histomorphometric analysis. Collected data were subjected to analysis of variance supplemented by the Tukey-Kramer test (p<0.05). RESULTS: the ctrl group and the ones treated with different doses of GEN showed atrophic mammary glands, whereas the glands were more developed in the ECE group, where numerous mammary ducts and alveoli were observed. Morphometry showed a larger area of mammary parenchyma in the ECE group (98.870.1±550.4 µm²* per mm²; p<0.05) compared with other groups (Ctrl=36.875.6±443.4; GEN46=37.001.7±557.4; GEN125=36.480.8±658.3 and GEN250=37.502.8±669.3). The same occurred in the number of alveoli in the ECE group (33.2±6.9* per mm²; p<0.05) compared to the other groups (Ctrl=10.4±2.1, GEN46=11.2±3.1; GEN125=11.6±2.1 and GEN250=12.3±2.3). The estradiol level was higher in the ECE group compared to the other groups (9.4±1.7 pg/mL; p<0.05), whereas serum levels of progesterone were similar in all groups. CONCLUSION: the administration of genistein at high doses had no trophic effect on the mammary glands of rats.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2011;33(7):137-142
DOI 10.1590/S0100-72032011000700004
PURPOSE: To evaluate the efect of trimegestone on the histological changes of the mammary tissue of castrated rats. METHODS: Forty-five virgin female Wistar rats were used after oophorectomy. Sixty days after surgery, with hypoestrogenisms confirmed, the experimental rats were randomly assigned to three groups of 15 animals each, when then the specific treatment for each group was started. The control group (C) and experimental groups 1 and 2 respectively received 0.9% saline solution, 17-beta-estradiol and 17-beta-estradiol in combination with trimegestone for 60 consecutive days. After the end of treatment , the inguinal mammary glands were removed, stained with hematoxylin and eosin (HE) for morphometry and examined by immunohistochemistry for the quantification of anti-PCNA antibody in the mammary tissue, followed by euthanasia. The morphometric parameters evaluated were: epithelium cell-proliferation, secretor activity and mammary stroma changes. There were nine deaths during the experiment. The variables were submitted to statistical analysis adopting the 0.05 level of significance. RESULTS:Histological changes were observed in 16/36 rats, mild epithelial hyperplasia in 13/36, moderate epithelial hyperplasia in 3/36, with no cases of severe epithelial hyperplasia. Stromal fibrosis was found in 10/36 and secretory activity in 5/36 rats. All morphometric variables were significant in the estrogen group compared to control (p=0.0361), although there were no difference between the group receiving combined treatment and the controls (p=0.405). The immunohistochemical analysis showed no difference between groups. CONCLUSIONS:The hormones administered to castrated rats, i.e., 17 beta-estradiol alone or in combination with trimegestone, increased the proliferation of breast cells, but this effect appeared to be lower in the combined treatment, the same occurring regarding fibrosis of the mammary stroma.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2011;33(7):137-142
DOI 10.1590/S0100-72032011000700004
PURPOSE: To evaluate the efect of trimegestone on the histological changes of the mammary tissue of castrated rats. METHODS: Forty-five virgin female Wistar rats were used after oophorectomy. Sixty days after surgery, with hypoestrogenisms confirmed, the experimental rats were randomly assigned to three groups of 15 animals each, when then the specific treatment for each group was started. The control group (C) and experimental groups 1 and 2 respectively received 0.9% saline solution, 17-beta-estradiol and 17-beta-estradiol in combination with trimegestone for 60 consecutive days. After the end of treatment , the inguinal mammary glands were removed, stained with hematoxylin and eosin (HE) for morphometry and examined by immunohistochemistry for the quantification of anti-PCNA antibody in the mammary tissue, followed by euthanasia. The morphometric parameters evaluated were: epithelium cell-proliferation, secretor activity and mammary stroma changes. There were nine deaths during the experiment. The variables were submitted to statistical analysis adopting the 0.05 level of significance. RESULTS:Histological changes were observed in 16/36 rats, mild epithelial hyperplasia in 13/36, moderate epithelial hyperplasia in 3/36, with no cases of severe epithelial hyperplasia. Stromal fibrosis was found in 10/36 and secretory activity in 5/36 rats. All morphometric variables were significant in the estrogen group compared to control (p=0.0361), although there were no difference between the group receiving combined treatment and the controls (p=0.405). The immunohistochemical analysis showed no difference between groups. CONCLUSIONS:The hormones administered to castrated rats, i.e., 17 beta-estradiol alone or in combination with trimegestone, increased the proliferation of breast cells, but this effect appeared to be lower in the combined treatment, the same occurring regarding fibrosis of the mammary stroma.
