Protective effect of vitamin E on cypermethrin-induced follicular atresia in rat ovary: Evidence for energy dependent mechanism

It has been shown that chronic exposure to cypermethrin (CPM), a pyrethroid pesticide, results in follicular atresia via pathologically affecting angiogenesis, disrupting endocrine potential and enhancing oxidative stress. This study was aimed to uncover the CPM-exposed energy dependent follicular cells apoptosis and to estimate protective effect of vitamin E (VitE) as a potent antioxidant. Thirty six Wistar rats were divided into six groups (n = 6 rats for each group) including; control-sham, CPM-received (CPM, 75 mg kg(-1), intraperitoneally), and CPM and VitE-treated (VitE, 150 mg kg(-1), orally) for 14 and 24 days. The protein biosynthesis of glucose transporter-1 (GLUT-1) and caspase-3 in follicles were estimated by using immuno-histochemical staining at preantral and antral stages. Moreover, the periodic acid Schiff (PAS) staining was performed in order to evaluate the intracytoplasmic carbohydrate ratio in follicular cells and oocyte. Percentages of follicles with GLUT-1, Caspase-3 and PAS-positive cells were compared between groups. Immunohistochemical analyses showed that, VitE significantly up-regulated the GLUT-1 expression and improved the intracytoplasmic carbohydrate supplementation especially at preantral follicles. The cross sections from the CPM-exposed ovaries represented remarkable elevation in percentage of atretic preantral and antral follicles with caspase-3 biosynthesis, which was remarkably (p < 0.05) diminished in VitE co-treated groups. In conclusion, our data showed that VitE by up-regulating of the GLUT-1 biosynthesis improved glucose uptake at follicular cells and oocyte levels that in turn inhibited pro-apoptotic protein caspase-3 biosynthesis.