Effects of hysterectomy on ovulation and related ovarian functions in regular estrous cycle rats

What is the impact of PPAR-γ agonist-rosiglitazone on ovarian reserve after hysterectomy? An experimental study

Background/aim

To evaluate the effects of hysterectomy on rat ovaries and the possible protective role of peroxisome proliferator-activated receptor gamma (PPAR-γ) agonist-rosiglitazone against ovarian reserve decrement.

Materials and methods

Forty-five adult Wistar albino rats were randomly divided into three groups. Hysterectomy was performed (n = 15) in group 1 [H]; 1 mg/kg/day PPAR-γ agonist/rosiglitazone was used for 50 days after hysterectomy (n = 15) in group 2 [H + R]; a sham operation was performed (n = 15) in group 3 [control, C]. Blood samples were collected for anti-Müllerian hormone (AMH) evaluation in all groups and simultaneous ovarian Doppler examination was performed in [H] and [H + R] groups before and after (50 days) hysterectomy. All animals were sacrificed to obtain ovaries for histological examination.

Results

AMH levels were found to be significantly decreased at postoperative day 50 in all groups (P < 0.05). Histopathologic analysis showed that primary, preantral, and antral follicle counts were significantly higher in the [H] group as compared to the [C] and [H + R] groups (P < 0.05). There was no significant difference between the [C] and [H + R] groups in terms of follicle numbers (P > 0.05). In the ovarian Doppler blood flow analysis, all parameters were significantly decreased in group [H] (P < 0.05), but not in the [H + R] group (P > 0.05) on postoperative day 50.

Conclusion

Hysterectomy affects the histopathological structure of rat ovaries and PPAR-γ agonist-rosiglitazone improves the ovarian Doppler blood flow parameters.

Hysterectomy Uniquely Impacts Spatial Memory in a Rat Model: A Role for the Nonpregnant Uterus in Cognitive Processes

Approximately one-third of women experience hysterectomy, or the surgical removal of the uterus, by 60 years of age, with most surgeries occurring prior to the onset of natural menopause. The ovaries are retained in about half of these surgeries, whereas for the other half hysterectomy occurs concurrently with oophorectomy. The dogma is that the nonpregnant uterus is dormant. There have been no preclinical assessments of surgical variations in menopause, including hysterectomy, with and without ovarian conservation, on potential endocrine and cognitive changes. We present a novel rat model of hysterectomy alongside sham, ovariectomy (Ovx), and Ovx-hysterectomy groups to assess effects of surgical menopause variations. Rats without ovaries learned the working memory domain of a complex cognitive task faster than did those with ovaries. Moreover, uterus removal alone had a unique detrimental impact on the ability to handle a high-demand working memory load. The addition of Ovx, that is, Ovx-hysterectomy, prevented this hysterectomy-induced memory deficit. Performance did not differ amongst groups in reference memory-only tasks, suggesting that the working memory domain is particularly sensitive to variations in surgical menopause. Following uterus removal, ovarian histology and estrous cycle monitoring demonstrated that ovaries continued to function, and serum assays indicated altered ovarian hormone and gonadotropin profiles by 2 months after surgery. These results underscore the critical need to further study the contribution of the uterus to the female phenotype, including effects of hysterectomy with and without ovarian conservation, on the trajectory of brain and endocrine aging to decipher the impact of common variations in gynecological surgery in women. Moreover, findings demonstrate that the nonpregnant uterus is not dormant, and indicate that there is an ovarian-uterus-brain system that becomes interrupted when the reproductive tract has been disrupted, leading to alterations in brain functioning.

Does hysterectomy affect ovarian function? Histopathologic evaluation and serum FSH, inhibin A, and inhibin B levels in an experimental rat model

OBJECTIVE

To evaluate the effects of hysterectomy with ovarian conservation on ovarian histology, and FSH, inhibin A, and inhibin B plasma levels.

STUDY DESIGN

Forty-five female Wistar albino rats were used in this study and randomly divided into two groups: hysterectomy (n=30) and sham-operated (n=15). Blood samples were collected before and after (50 and 100 days) abdominal hysterectomy from both groups to measure plasma levels of FSH, inhibin A, and inhibin B. All animals were sacrificed by decapitation to obtain ovaries for histological examination. For statistical analyses, Mann-Whitney U, Chi-square, Wilcoxon matched pairs signed rank sum tests, and two-sided variance analysis were used and statistical significance was defined as p<0.05.

RESULTS

There was no difference in hormonal variables between groups when the time interval was considered completely [p>0.05 (for FSH p=0.962; for inhibin A p=0.321; for inhibin B p=0.476)]. In the hysterectomy group, the inhibin B level at postoperative day 50 was significantly lower than the control group (p=0.007) and at postoperative day 100, inhibin A concentrations were increased significantly when compared with the levels at both baseline and postoperative day 50 (p<0.001). Histopathologic evaluation of ovaries 100 days after hysterectomy showed that ovaries from the hysterectomy group had significantly fewer primary (p=0.01), preantral (p<0.001), and antral follicles (p<0.001), and significantly more corpora lutea (p<0.001), atretic (p=0.02), and cystic follicles (p=0.003).

CONCLUSION

The results of this experimental rat model suggest that hysterectomy may affect ovarian function.

Effects of hysterectomy on ovarian morphology and serum FSH level in rats

OBJECTIVE

To investigate the effects of hysterectomy with ovarian conservation on ovarian histology and FSH plasma level.

METHODS

Fifty female Wistar albino rats (30 for hysterectomy and 20 sham operated for control) were used after two complete estrous cycles. Six months after hysterectomy, the blood samples were collected from both the groups to test FSH plasma level and all animals were sacrificed by decapitation to obtain ovaries for histological examination.

RESULTS

Histologic study showed that ovaries from control group exhibited many follicles in various stages of development including primary, secondary and tertiary follicles. There were one or two secondary and tertiary follicles but no primary follicle in each histological section of the 6 months after hysterectomy. The ovaries showed that the cortex of ovary completely covered by corpora lutea, and there were many cystic follicles and atretic follicles with few normal follicles. Theca interna is absent in cysts and most of the mural granulose cell population has been depleted. Serum FSH levels showed significantly increase in hysterectomized group compared control after 6 months operation.

CONCLUSIONS

The results of present study support previous studies and suggest that hysterectomy with ovarian conservation in young patients could preserve a woman's normal hormonal milieu. The uterus could have controlling on ovulation and hysterectomy might accelerate to initiate of early menopause.

Lack of influence of hysterectomy on meal size and meal number in Fischer-344 rats

Based on our previous observation that, when eating the same amount of food per 100 g b.wt., male rats gain five to seven times more weight than females who have an estrous cycle every 4 to 5 days, we questioned whether lower weight gain seen in female rats could be the result of increased energy cost in preparing endometrium for anticipated fertilization. Because the uterus modulates estrogenic effects on other hormone-dependent behaviors, for example, sexual receptivity and lordosis, we performed this study to determine if estrogen-mediated cyclical changes in food intake and feeding pattern occur after hysterectomy. Fifteen female Fischer 344 rats were randomized during the estrous phase to either hysterectomy with ovarian preservation or sham operation. A rat eater meter was used to continuously measure food intake, meal number, and meal size for two estrous cycles before and four cycles after surgery. Both groups showed the estrous phase linked cycling in meal number, meal size, and food intake. No differences existed between the two groups in these indices either before or after surgery. No differences existed between groups in rate of body weight gain after surgery, 0.95 +/- 0.13 g/day in hysterectomized and 0.77 +/- 0.1 g/day in sham-operated rats. We conclude that hysterectomy has no effect on rate of weight gain, food intake, and estrus linked cyclical feeding pattern in Fischer 344 rats.