Curcumin, as a pleiotropic agent, improves doxorubicin-induced nephrotic syndrome in rats

Ethnopharmacological relevance: Curcumin, a phenolic compound extracted from the rhizome of turmeric (Curcuma longa L.), has been reported to have broad biological functions including potent antioxidant and renoprotective effects. It has been reported that Curcumin has a certain protective effect on the kidney. However, its mechanism of action needs further study. Aim of the study: The present research aims at investigating the therapeutic effects and its underlying mechanism of curcumin on NS. Materials and methods: The conditionally immortalized mouse podocyte cell line was utilized to evaluate the podocyte-protective effect of curcumin and its effects on NF-kappa B pathway and Nrf2/ARE pathway in podocyte in vitro. Furthermore, the DOX-induced NS rats were utilized to investigate the therapeutic effects and its underlying mechanism of curcumin against NS in vivo. Results: The consequences of this study revealed that curcumin activated Nrf2, inhibited NF-kappa B pathway and upregulated podocin in DOX-induced podocyte. Further research results showed that curcumin can considerably alleviate proteinuria and improve hypoalbuminemia in NS rats, and lower blood lipid levels to alleviate hyperlipidemia in NS rats, indicating that curcumin has significant therapeutic effects on rat NS. Further observation by electron microscopy and detection showed that curcumin can improve renal function and podocyte injury, which may be related to the repairment of mRNA expression and podocin protein. Interestingly, the results of the blood rheology test showed that curcumin can effectively reduce whole blood viscosity (WBV) and plasma viscosity (PV), and reduce hematocrit (Hct). In addition, the oxidative stress state of kidney in NS rats was considerably reversed by curcumin, which may be achieved by activating Nrf2 and increasing the expression of antioxidant enzymes HO-1, NQO-1. We also found that NF-kappa B pathway is activated in the kidney of NS rats, and curcumin can inhibit the activation of NF-kappa B by down-regulating the expression of NF-kappa B p65, reducing the level of p-I kappa B alpha and up-regulating the expression of I kappa B alpha. Conclusion: These findings suggest that curcumin, as a multifunctional agent, exerts a protective effect on DOXinduced nephrotic syndrome in rats, which provides a pharmacological basis for the further development of curcumin and also provides a basis for the advantages of multi-targeted drugs in the processing of NS.