Polysaccharide extract of Cordyceps sobolifera attenuates renal injury in endotoxemic rats

Extracts derived from Cordyceps have been demonstrated to possess various pharmacological effects, including immunomodulatory, antitumor, hypoglycemic, and antioxidant activities. This study was aimed to clarify the role of CS-P, a polysaccharide fraction isolated from Cordyceps sobolifera, in modulating nephrofunctional damage in a rat model of endotoxemia. CS-P (500 mg/kg body weight) was orally administered to rats for 4 weeks before the peritoneal injection of lipopolysaccharide (LPS, 10 mg/kg body weight). Pre-treatment with CS-P significantly attenuated the deleterious renal functions caused by LPS, i.e., elevated blood urea nitrogen and creatinine as well as urine protein. Histopathological examination of kidney tissues also demonstrated that CS-P improved LPS-induced pathological abnormalities. The induction of inducible nitric oxide synthase and the overproduction of nitric acid by LPS were also significantly reduced by CS-P via inhibiting nuclear factor-κB activation. In addition, CS-P pre-treatment suppressed the plasma levels of tumor necrosis factor-alpha and interleukin-6. Concurrently, CS-P supplementation potently suppressed the LPS-induced rise of lipid peroxidation and markedly enhanced the antioxidant defense system by restoring the levels of superoxide dismutase, glutathione peroxidase, and catalase in kidney. The present results suggested that CS-P pre-treatment could protect against LPS-triggered inflammatory responses and renal injury in rats.