The protective effect of Rubia cordifolia against lead nitrate-induced immune response impairment and kidney oxidative damage

OBJECTIVES: To evaluate the in vivo antioxidant activity of the ethanolic extract of the roots of Rubia cordifolia (RC) and to study its influence on lead nitrate-induced impairment of immune responses. MATERIALS AND METHODS: Seventy-two adult male Swiss albino mice were used for biochemical and immunological studies and were divided into six groups of six mice each. Mice were treated with lead nitrate (40 mg/kg, orally) either alone and or in combination with RC (50 and 100 mg/kg body weight) daily for 40 days. For immunological studies, all mice were challenged twice with sheep RBC with on days 14 and 20 of the experiment. The immune function was assessed using macrophage yield, viability of macrophage, phagocytic index, serum immunoglobulin level, and plaque forming cell count (PFC), whereas the oxidative stress was assessed by estimating lipid peroxidation (LPO), reduced glutathione (GSH) content, and the activities of superoxide dismutase (SOD) and catalase (CAT). RESULTS: Lead nitrate administration induced a significant (P<0.001) increase in LPO, whereas a significant (P<0.001) depletion of CAT and GSH in renal tissues. In addition, it also showed a significant (P<0.001) reduction in macrophage yield, viability of macrophage, phagocyte index, serum immunoglobulin level, and PFC in kidney. However, combination treatment with RC observed a significant (P<0.001) reversal of lead nitrate-induced toxicity on oxidative stress and immunological parameters. CONCLUSION: The lead nitrate-induced immunosuppression is due to oxidative stress and RC can prevent the same by virtue of its in vivo antioxidant property.