Journal of Reproduction & Infertility
Volume:9 Issue: 3, 2009

Wnt signaling pathway plays an important role in folliculogenesis of rodent ovaries; however, its involvement in ovarian apoptotic events remains undetermined. With respect to the importance of apoptosis in homeostasis and ovarian biological function, this experimental study was conducted to determine the effects of Wnt/ß-catenin signaling on follicular growth arrest and apoptosis in polycystic ovary (PCO) models of rats.

The experiments were performed in three independent series and with each set of experiments, 8 rats were allocated to the group, half of them as the controls and the other four as the testosterone propionate (TP)-treated rats for the indicated period of time (1 and 4 weeks). Induction of PCO in immature rats was performed by daily injection of testosterone propionate (TP) dissolved in sesame oil over 1 and 4 weeks in the experimental group but to the control group solvent was injected. At the end of the experiments, the ovaries were fixed and sequential paraffin slices were prepared for immunohistochemical analyses of GSK3ß, ß-catenin and pGSK3ßser9 proteins. Assessment of Sfrp4 expression as an antagonist of Wnt signaling pathway was performed by Western blot test. Analysis of apoptosis was done by TUNEL staining, followed by quantification of apoptotic follicles in the different groups. The data were analyzed by using Mann-Whitney U-test and a p-value <0.05 was considered significant.

Histological analysis of TP-treated rats showed cystic follicles, absence of corpus luteum and anovulation. GSK3ß expression in apoptotic follicles of PCO-induced and control groups was observed. In addition, co-localization of nuclear ß-catenin and pGSK3ßser9 in 1-week-treated rats was detected. In long-term TP-treated rats, there was an increase in apoptosis and GSK3ß expression and a 5.1 fold increase in Sfrp4 expression in granulosa cells, compared with the control group, which may explain the absence of nuclear ß-catenin in these cells.

The results show testosterone propionate injections induces PCO in immature rats. Furthermore, the increased expression of Sfrp4 and GSK3ßin long-term treatment with TP was associated with apoptosis. These results may reveal Wnt signaling inhibition in apoptotic events of rodent ovaries.

Selenium, as an antioxidant, is essential for normal testicular function and spermatogenesis. It can reduce free oxidative radicals as a cofactor for antioxidant enzymes; therefore, it is expected to increase fertility. This experimental study was conducted to determine the effects of different doses of selenium on sperm parameters and testicular structure of aged and young mice.

In this study, twenty 10 to 12-month and twenty 2 to 3-month old male mice were randomly divided into three control, sham and experimental groups. The control group received no injection but the sham and the experimental groups received daily intraperitoneal injectins of selenium solvent (Normal saline) and selenium, 0.2 mg/kg (Based on dose/response data), respectively over 5 weeks. Histological examinations as well as sperm analyses were performed on days 21, 28, 35 and 42 following the initiation of injections.

Sperm analyses showed improvements especially in terms of normal morphology and viability rates in the experimental group (P<0.05). Decreased sperm counts were evident in the aged mice at histological examination and some vacuoles were observable in the epithelium of seminiferous tubules.

The results indicated that administration of 0.2 mg/kg selenium, improves some sperm parameters in the aged mice; thus, it seems that selenium effects are dose-dependent and appropriate amounts of the element can probably improve testicular function and sperm quality in the aged subjects.