Effects of short term dietary zinc deficiency and zinc supplementation on nitro-oxidative stress in testes of Wistar rats.

Abstract

Zinc is crucial for several cellular functions in the biological system. Zinc insufficiency is one of the most prevalent types of micronutrient malnutrition in the world. Present study was conducted to detect testicular free radical levels i.e. lipid peroxidation (LPO), hydroperoxides, hydroxyl radical (OH^.), nitric oxide (NO) and peroxynitrite (ONOO^-) after short term dietary zinc deficiency and zinc supplementation. Pre-pubertal rats (n = 144) were divided into two groups with 6 sub-groups viz. zinc control (ZC, 100 µg/g zinc diet), pair-fed (PF, 100 µg/g zinc diet), zinc deficient (ZD, < 1.00 µg/g), zinc control supplementation (ZCS, 100 µg/g zinc diet), pair-fed supplementation (PFS, 100 µg/g zinc diet) and zinc deficient supplementation (ZDS, 100 µg/g zinc diet). Experiments were set for 2- and 4-weeks followed by 4 weeks of dietary zinc supplementation. Zinc deficient groups (2- and 4-weeks) exhibited significant (p < 0.05) increase in testicular LPO (TBARS), hydroperoxides, OH^·, NO and ONOO^- levels as compared to their respective control and pair-fed groups. Zinc deficient supplementation group (2ZDS) revealed a non-significant increase in OH^·, NO and ONOO^- levels while a significant increase in LPO and hydroperoxides levels. 4ZDS group showed a significant increase in the free radical levels, however the increase was less as compared to 4ZD group. Dietary zinc deficiency results in induction of cellular lipoperoxidation as well as causes stimulation of nitro-oxidative stress. Zinc supplementation (although for short duration signifying zinc redistribution in the testicular tissue) indicated positive response accounting for reduced free radical generation and also implicating its requirement in optimum level for sustentation of reproductive functions.