| Part I In Vivo Study on the Effects of Fenvalerate and Phoxim onthe Function of Rat OvaryObjective To investigate the effects of fenvalerate (Fen) and Pho (Pho) on the ovarian antioxidant function.Methods Fen and Pho were administrated ig to the adult female Sprague Dawley rats at dose of 1.91, 9.55, 31.80mg/kg and 5.88, 29.4, 98 mg/kg respectively for one month. Vaginal smears of rats were performed to determine estrous cycle. Some organs such as ovary, uterus, brain, liver,spleen, kidney and adrenal were dissected and organ coefficients were calculated. The activities of superoxide dismutase (SOD) and glutathione-s-transferase (GST), and the levels of malondialdehyde (MDA) and glutathione (GSH) in the ovary and serum were measured by photometry. The estradiol (E) and progesterone (P) in the serum were determined by radioimmunoassay (RIA). Total DNA was extracted from ovary and the DNA fragmentation was valued by agarose gel electrophoresis. The expression of bcl-2 protein in the ovary was observed with SP immunohistochemical method. The morphological changes and ultrastructure of ovary were examined by the light and electronic microscopy.Results In the Fen group, the rate of estrous cylce abnormality significantly increased and the gain of body weight was obviously lower in 31.80mg/kg group than that of control. Proestrus and metestrus prolonged significantly in 1.91mg/kg and 31.80mg/kg group than that of the control and the duration of estrus and diestrus was reduced. The relative organ weights (ovary, uterus) were declined in a dose dependent manner, which was markedly reduced at the dose of 31.80mg/kg. Fen increased the levels of SOD and GSH in ovary and decreased the content of MDA. The levels of GST declined obviously. On the contrary, the SOD and GST activities in the serum of exposed rats were reduced while the content of MDA was enhanced. The synthesis of E was stimulated-6-significantly by Fen in serum at doses of 9.55 and 31.80mg/kg while the level of P was declined obviously. The expression of bcl-2 protein in ovary was up-regulated by Fen in 9.55mg/kg group. Pho increased the rate of estrous cycle abnormality significantly and reduced the gain of body weight obviously in 98mg/kg group than that of control. No any obvious change was observed in the duration of each estrous cycle in the exposed groups. Meanwhile, the ovary and uterus weights were declined in a dose dependent manner. Pho increased the levels of SOD, GST and GSH in ovary and decreased the content of MDA. On the contrary, the SOD and GST activities in the serum of exposed rats had been markedly reduced than that of the control while the contents of MDA was enhanced. No any significant effect of E and P was observed in Pho Treated group. The expression of bcl-2 protein in ovary was increased in low dose group. The morphological changes under the light and electronic microscopy examination indicated that the amount of atrestic follicle in the Fen and Pho exposed groups was increased, but there is no obvious alteration in atrestic follicle of treated group as compared with the control. The ultrastructure changes of ovary under the electronic microscopy indicated that parts of endoplasmic reticulum expanded, mitochondria vacuolized and cristae lost in the Fen group. Nucleolus showed margin assemblling. The morphological alterations in Pho group showed the increase and enlargement of the lipid dropletand the loss of-7-integrity of the nuclear membrane. Mictochondrial swelled and cristaedisappeared, and the matrix showed asymmetry.Conclusion The results suggest that Fen at the doses of 1.91, 9.55, and 31.80mg/kg could significantly disrupt the estrous cycle and secretion of hormone, while Pho at the doses of 5.88, 29.4, 98 mg/kg had not obvious effect as Fen did. Fen and Pho could induce the compensatory increase of antioxidant capacity and the action of Pho was more notable, yet they could not result in a significant damage to the antioxidant system of rat ovary.Key words fenvalerate; phoxim; rat; ovary; estrous...
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