Effect of Drinking Water Nitrates and Vitamin C on Rat Liver Enzymes and Oxidative Markers

Abstract

Background: Liver cells or hepatocytes facilitate different hepatic functions. The liver reportedly accounts for up to 500 separate functions, alongside other systems and organs. The high consumption of the food containing high levels of nitrate in the community and the presence of this harmful substance in water endanger the health of many people. N-nitroso compounds, as potential free radicals, can damage the tissues through oxidative stress. Objectives: The current study was targeted toward examining the impact of drinking water nitrate and vitamin C on hepatic enzymes and oxidative markers in rats. Methods: The present experimental study was performed on 49 rats in Mashhad, Iran, during 2017 - 2018. The subjects were assigned into seven groups. Group one received water without nitrates (control) while groups two, three, and four received different concentration of nitrates (10, 45, 200 mg/L). Groups five, six, and seven received the same concentration of nitrates and vitamin C (20 mg/100g body weight). After 91 days, blood samples were obtained to determine hepatic enzymes (namely, ALT/SGPT: alanine aminotransferase, AST/SGOT: aspartate aminotransferase, and ALP: alkaline phosphatase). Furthermore, an autopsy was carried out to examine the liver tissue regarding the markers of oxidation (namely, MDA: Malondialdehyde, SOD: Superoxide-dismutase, CAT: Catalase enzyme, and GSH: Glutathione), according to the protocol. Results: The results revealed a significant elevation in ALP (P = 0.034), AST (P = 0.018), and ALT (155.14 ± 25.67, 92 ± 17.72, P = 0.000), compared to those in the control group. In addition, the fourth group demonstrated a significant enhancement in MDA level, collated to the group one (P = 0.44), while there was a significant drop in CAT (P = 0.025), SOD (P = 0.002), and GSH levels (P = 0.000). Furthermore, use of vitamin C led to a significant drop in the levels of ALP, AST, ALT, and MDA, as well as a significant elevation in GSH, SOD, and CAT in the seventh group in comparison to the fourth group (P < 0.05). Conclusions: As the findings indicated, drinking water nitrate and Vitamin C exerted a non-significant effect on the doses of nitrate (10 and 45 mg/L). Nonetheless, a nitrate dose of 200 mg/L had a significant impact on ALT, ALP, AST, and oxidative stress indicators leading to hepatic diseases.