Protective effects of fraction 4a of polysaccharides isolated from Lycium barbarum against KBrO3-induced renal damage in rats

Abstract

Potassium bromate (KBrO₃) is widely used as a food additive and is a major by-product of water disinfection. The aim of this study was to investigate the protective effects of fraction 4a of polysaccharides isolated from Lycium barbarum (LBP-4a) against renal damage induced by KBrO₃ in rats and to determine the relevant mechanisms behind these effects. Male Wistar rats were divided into a normal control group, a KBrO₃ control group, and LBP-4a(L) and LBP-4a(H) groups. With the exception of the normal control group, the rats in the other three groups were administered KBrO₃ by intraperitoneal injection to induce renal damage. Before the induction of renal damage, rats in the LBP-4a(L) and LBP-4a(H) groups were pretreated with 50 mg per kg b.w. or 100 mg per kg b.w. LBP-4a, respectively, by intragastric administration. Clinical biochemical parameters and markers of oxidative damage were also determined. Treatment by administration of LBP-4a prior to challenge with KBrO₃ prevented increases in the levels of nitrite, creatinine, urea nitrogen and uric acid in serum and increased the activities of antioxidant enzymes in kidney tissues. A comet assay and FCS results showed that pretreatment with LBP-4a also alleviated DNA damage and decreases in mitochondrial membrane potentials in renal cells. Histological studies further supported the above results and showed extensive renal damage in animals treated with KBrO₃ and greatly reduced tissue injury in groups pretreated with LBP-4a. In conclusion, LBP-4a exhibited protective effects against renal damage induced by KBrO₃, and the mechanism was closely correlated with a reduction in levels of lipid peroxidation and an increase in the activities of antioxidant enzymes in kidney tissues, which alleviated DNA damage and increased mitochondrial membrane potentials in renal cells. These observations provide the background for the further development of LBP-4a as a protective agent for use in the treatment of renal damage.