Chronic Administration of Combined Oral Contraceptive Pill Causes Prefrontal Cortical Oxidative Stress in Female Wistar Rats

Combined oral contraceptive pill (COCP) is used by women to prevent ovulation. This study investigated toxicological effects of COCP on the brain of female rats. Fifteen rats were divided at random into three groups (n=5): Normal control, and first and second cycles treated orally with COCP (0.04 μg/kg bwt of ethinyl oestradiol and 2 μg/kg bwt levonorgestrel) daily for 21 and 42 days respectively. Toxicological effect of treatment on the brain was assessed in the prefrontal cortical acetylcholinesterase, sodium/potassium-ATPase (Na+/K+-ATPase), superoxide dismutase and catalase activities, lipid peroxidation and reduced glutathione levels. Histomorphological examination of the prefrontal cortex of the rats in all the groups was carried out. Activities of cortical Na+/K+-ATPase, acetylcholinesterase, superoxide dismutase and catalase were significantly (p<0.05) reduced following chronic administration of COCP. Histomorphological study of the pre-frontal cortex showed large pyramidal neurons, pyknotic pyramidal neurons, condensed nuclei and increased perineural spaces. Results showed that chronic administration of oral contraceptive caused prefrontal cortical oxidative stress by repressing activities of antioxidant enzymes, Na+/K+-ATPase and acetylcholinesterase.