The effects of conjugated estrogen, raloxifene and soy extract on collagen in rat bones.

OBJECTIVE: To evaluate the action of conjugated equine estrogen, raloxifene and isolated or combined genistein-rich soy extracts on collagen fibers in the bones of oophorectomized rats. MATERIALS AND METHODS: Seventy female rats received testosterone propionate (0.1 µg/g) on the 9th day after birth. At 6 months of age, the rats were administered the vehicle (propylene glycol, 0.5 ml/day), and ten of the rats were randomly chosen to comprise the non-oophorectomized control group (GI). The other 60 rats were ovariectomized and randomized into six groups of ten as follows: GII, vehicle; GIII, conjugated equine estrogen (CEE), 50 µg/kg/day; GIV, raloxifene (RAL), 0.75 mg/kg/day; GV, genistein-rich soy extract (GSE), 300 mg/kg/day; GVI, CEE + GSE, 50 µg/kg/day + 300 mg/kg/day; and GVII, CEE + RAL, 50 µg/kg/day + 0.75 mg/kg/day. Three months after surgery, the drugs were administered for 60 consecutive days. All rats were euthanized, and their left tibiae were removed for histological routine. The histological sections were stained with hematoxylin-eosin, and picrosirius for evaluating bone microarchitecture. Types I and II collagen fibers were analyzed by immunofluorescence. Data analysis was carried out with ANOVA and Tukey's test. RESULTS: Collagen reduction was significant in the GIII animals when compared to the other groups (p < 0.05). There was no significant difference in the thickness of collagen fibers among the groups. There was a greater quantity of type III collagen in GVI than in the other groups. CONCLUSION: Our data indicate that conjugated equine estrogen improves bone quality because it increases the quantity of type I collagen while reducing the quantity of thin collagen fibers. In addition, the combination of CEE and raloxifene or genistein-rich soy extract is not as efficient as CEE itself to improve bone quality.

Extended administration of the association of zidovudine plus ritonavir during rat pregnancy: maternal and fetal effects.

The purpose of the study was to evaluate at term, the effects of the association of zidovudine/ritonavir administered during the entire period of rat pregnancy. Forty pregnant EPM-1 Wistar rats were divided randomly into four groups: one control (drug vehicle control, n=10) and three experimental treated with an oral solution of zidovudine/ritonavir (Exp 1 = 10/20 mg/kg bw, n = 10; Exp 2 = 30/60 mg/kg bw, n=10; Exp 3 = 90/180 mg/kg bw, n=10) from day 0 up to day 20 of pregnancy. Maternal body weights were recorded at the start of the experiment and at the 7th, 14th and the 20th day thereafter. At term (20th day) the rats were anesthetized and, upon laparotomy and hysterotomy, the number of implantations, resorptions, living fetuses, placentae and intrauterine deaths were recorded. The collected fetuses and placentae were weighed, and the concepts were examined under a stereoscopic microscope for external malformations. The maternal body gain and the mean fetal weight at term were both significantly lower (p < 0.01 and p < 0.0001, respectively) in the experimental groups compared to the control. The recorded resorptions were higher in Exp 2 and Exp 3 groups than in the control group. The other parameters were not affected. The exposure of pregnant rats at term to a 1:2 association of zidovudine plus ritonavir resulted in a significant reduction in maternal body weight gain and increased rate of fetal resorption.

Impact of pregnancy and childbirth on female rats' urethral nerve fibers.

This study aims to evaluate the urethral nerve fibers of adult female rats during pregnancy and after vaginal birth, cesarean section or simulated birth trauma. For immunohistochemical analysis of nerve fibers, 70 female rats were distributed in seven groups of ten female rats: group 1, control; group 2, pregnant; group 3, cesarean section; group 4, vaginal birth; group 5, virgin female rats with simulated birth trauma; group 6, cesarean section followed by simulation of birth trauma; and group 7, vaginal birth followed by simulation of birth trauma. The number of nerve fibers in groups 1, 2, and 3 were significantly higher than the other groups. Pregnancy and cesarean section did not cause alterations in the nerve fibers number. Vaginal birth and simulated birth trauma significantly decreased the number of nerve fibers in the female rats' middle urethra.

The impact of pregnancy and childbirth in the urethra of female rats.

The aim of this study was to evaluate the modifications in the amount of collagen, muscular, and elastic fibers in the mid-urethra of adult female rats during the pregnancy and after the natural childbirth, cesarean, and after simulated trauma of childbirth. The authors evaluated the histomorphometric aspects (collagen, muscular, and elastic fibers) in the mid-urethra of 70 animals distributed in seven groups: group 1 (n = 10)--control, group 2 (n = 10)--pregnant female rats, group 3 (n = 10)--female rats submitted to cesarean, group 4 (n = 10)--female rats with natural childbirth, group 5 (n = 10)--virgin female rats with simulated trauma of childbirth, group 6 (n = 10)--female rats submitted to cesarean followed by simulation of childbirth trauma, and group 7 (n = 10)--female rats with natural childbirth followed by simulation of childbirth trauma. The average concentration of collagen and elastic fibers and the collagen/muscular fiber correlation in groups 1, 2, and 3 were similar and significantly inferior to groups 4, 5, 6, and 7. The average of muscular fibers was similar in groups 1, 2, and 3 and significantly superior to groups 4, 5, 6, and 7. Pregnancy and cesarean did not induce alterations in collagen, muscular, and elastic fibers. However, the vaginal delivery and simulation of childbirth trauma determined the decrease in muscular fibers and the increase in collagen and elastic fibers and the correlation collagen/muscular fiber.

Morphological and morphometric changes in the cervix uteri of the rat at term pregnancy induced by hyaluronidase.

Intracervix injection of hyaluronidase during pregnancy has been proposed to accelerate cervix ripening. We evaluated the morphological and morphometric changes of the uterine cervix of pregnant rats, caused by the action of this enzyme. Ten female rats were equally divided between an experimental group (G II) and a control group (G I). On the 20th day of pregnancy, under light microscopy, a greater thinning of the superficial muciferous epithelium, with lamina propria rich in blood vessels and in eosinophils was found in G II. The histometric count of G II showed a smaller number of collagen fibers (average 248 vs 552 in the control group) and a greater concentration of eosinophils (average 18.20 vs 9.20 in the control group). The Student's t-test showed a significant difference in collagen fibers (p < 0.0001) and in eosinophils (p < 0.0007). The action of this enzyme caused a predominance of flaccid connective tissue, a lower concentration of collagen fibers and an increased concentration of eosinophils, confirming its utilization in cervix ripening.

Histomorphometric study of the inferior urinary tract of adult female rats during the interval between castration and hormonal replacement.

OBJECTIVE: To evaluate the epithelial thickness, number of vessels, amount of collagen and muscular fibers of the bladder and urethra of castrated adult female rats during the time between castration and the beginning of the administration of synthetic conjugated estrogen. METHOD: 118 adult female rats were divided into four groups: Group I (n = 30): noncastrated female rats; group II (n = 30): female rats treated with synthetic conjugated estrogen in the dose of 50 microg/animal/day for 28 days, beginning immediately after castration; group III (n = 28): female rats treated with synthetic conjugated estrogen, 50 microg/animal/day for 28 days, beginning 30 days after castration: group IV (n = 30): female rats sacrificed after 30 days of castration. The histology of the bladder wall and the medium-third of the urethra wall were evaluated after flushing with hematoxylin-eosin and picrosirius for morphometric analysis. RESULTS: It was verified that the epithelial thickness in groups II and III were similar whereas in groups I, II and III the thickness of the bladder and also the urethra were larger than in group IV. Concerning the bladder groups I and II were similar. In group I the urethra was superior than in groups II and III. In relation to the number of vessels and muscular fibers, groups I, II and III were similar to each other and superior to group IV in the bladder and urethra. The amount of collagen was similar in groups I, II and III and inferior in group IV in the bladder and in the urethra. CONCLUSION: Independent of the time of estrogen administration (immediate or within 30 days) after castration, the thickness of the epithelium, the number of vessels, amount of collagen and muscular fibers were similar. The female rats with estrogen replacement presented significantly larger thickness of the epithelium, number of vessels and muscular fibers, and a smaller amount of collagen in the bladder and urethra in relation to the castrated group. Finally, estrogen therapy (immediate and 30 days after castration) reverted the effects of the estrogen deficiency in the vessels, collagen and muscular fibers, the bladder and of the urethra when compared to the group of castrated female rats, thus becoming similar to noncastrated animals.

Evaluation of body weight in androgenized female rats.

PURPOSE: To evaluate the body weight of androgenized female rats or of rats in persistent estrus since these conditions mimic states of chronic anovulation in adult animals. METHODS: Forty-four Wistar-Hannover female rats were divided at random into two groups: control group (n = 17) which received only vehicle (0.1 ml corn oil) by the subcutaneous route on the second day of life, and experimental group (n = 27) which was similarly treated with 1.25 mg testosterone propionate diluted in 0.1 ml corn oil. The animals were weighed weekly from the fourth to the 12th week of life. Data were analyzed statistically by analysis of variance and by the Tukey-Kramer multiple comparisons test (p < 0.05). RESULTS: The experimental rats (androgenized or in persistent estrus) presented a significant increase in body weight starting on the fifth week of life compared to control rats. CONCLUSIONS: We conclude that androgenized rats present a significant increase in body weight, thus representing an interesting biological model for the study of diseases associated with excess weight and polycystic ovarian syndrome.

Quantitative evaluation of collagen and muscle fibers in the lower urinary tract of castrated and under-hormone replacement female rats.

OBJECTIVE: To evaluate the number of collagen and muscle fibers in the muscle layer of the urethra and in the bladder wall of castrated and under-hormone replacement female rats. METHOD: We studied 37 castrated female rats assigned to the following groups: Group C (n=9): received no medication; Group P (n=8) was given 0.1 ml of placebo, subcutaneous (SC) route; Group E (n=10): 17beta-estradiol, 10 microg/kg/day, SC route; Group PR (n=9): medroxyprogesterone acetate. 0.2 mg/kg/day, SC route; Group E+PR (n=9): association of 17beta-estradiol and medroxyprogesterone acetate. Sections were taken from the bladder wall and from the middle third of the urethra, and the specimens were stained with picrosirius for collagen and muscle fiber identification. RESULTS: Groups C and P showed a similar amount of collagen in the bladder and in the urethra, however greater than the other groups. Group E showed the smallest number of collagen fibers in the urethra. Groups E and E+PR presented a larger number of muscle fibers in the bladder. Group PR presented a larger number of muscle fibers than groups C and P, however smaller than groups E and E+PR. In the muscle layer of the urethra, the number of collagen fibers was smaller in Group E than in all the other groups, which were similar among one another. In regard to the urethral muscles, Group E was found to present the largest number of muscle fibers as compared to the other groups analyzed, while Group PR showed a significant decrease in the muscle layer, even in relation to the groups that were given no hormone medication. CONCLUSION: Estrogens significantly decrease the amount of collagen fibers, increase the amount of muscle fibers and determine a significantly decreased collagen/muscle ratio in both the detrusor muscle and in the urethral muscle layer. It is also noticed that isolated progestogen decreases the amount of collagen fibers and increases the number of muscle fibers in the detrusor muscle, but with less intensity than replacement with estrogens alone. It neither alters the number of collagen fibers nor decreases the muscle fibers in the muscle layer of the urethra, with increased collagen/muscle ratio in that structure. Finally, the estrogen-progestogen combination determines significantly decreased collagen fibers and increased muscle fibers in the detrusor muscle, causing no alteration to the collagen or muscle fibers in the muscle layer of the urethra.