The effects of vitamin B6 on lens antioxidant system in valproic acid-administered rats

Valproic acid (VPA, 2-propyl pentanoic acid) is a broad-spectrum antiepileptic drug (AED) and is commonly used in the treatment of bipolar disorders and epilepsy. AEDs are known to result in vascular disturbances. Vitamin B6 (Vit B6) is water soluble vitamin essential for normal growth, development, and metabolism. In this study, we aimed to investigate the protective effects of Vit B6 against VPA-induced lens damage in experimental animals. In this study, male 4-month-old, Sprague-Dawley rats were used. The animals were divided into four groups. Group I was intact control animals. Group II rats were administered with Vit B6 (50 mg/kg/day) for 7 days. Group III rats were administered with only VPA (500 mg/kg/day) for 7 days. Group IV was given VPA + Vit B6 (in a same dose and time). Vit B6 was given to rats by gavage and VPA was given by intraperitoneally. On the 8th day of experiment, all of the animals were fasted overnight and then killed under ether anesthesia. Lens tissues were taken from animals, homogenized in 0.9% saline to make up a 10% homogenate. The homogenates was used for glutathione (GSH), lipid peroxidation (LPO), protein levels, and enzyme analysis. In VPA groups, levels of lens GSH and LPO and activities of glutathione-S-transferase, glutathione peroxidase, glutathione reductase, and aldose reductase were increased, while superoxide dismutase activity was decreased. Treatment with Vit B6 reversed these effects. These results demonstrated that administration of Vit B6 is potentially beneficial agent to reduce the lens damage in VPA toxicity, probably by decreasing oxidative stress.