A 43 kD protein from the leaves of the herb Cajanus indicus L. modulates doxorubicin induced nephrotoxicity via MAPKs and both mitochondria dependent and independent pathways

Doxorubicin (Dox), a chemotherapeutic drug, is used for the treatment of different types of cancers. Application of this drug has now been made limited because of its several acute and chronic side effects. The aim of this work is to investigate the nephroprotecive role of a 43 kD protein (CI protein) isolated from the leaves of Cajanus indicus L, against Dox-induced oxidative impairment and kidney tissue damage. Administration of Dox (20 mg/kg body weight, once) significantly enhanced levels of blood urea nitrogen (BUN), creatinine, uric acid, TNF-α, urinary γ-glutamyl transpeptidase (γ-GT) activity, total urinary protein and urinary glucose level. Moreover, Dox exposure increased intracellular ROS production, lipid peroxidation, protein carbonylation and ATPases (like Na⁺/K⁺, Mg²⁺.) activities. On the other hand, the same exposure decreased GSH level and the activities of antioxidant enzymes; indicating that Dox-induced renal damage was mediated via oxidative stress. Signal transduction studies showed that Dox markedly decreased mitochondrial membrane potential, disturbed Bcl-2 family protein balance, enhanced cytochrome c release in the cytosol, increased levels of Apaf1, caspase-9/3/8, FAS, cleaved PARP protein and ultimately led to apoptotic cell death. In addition, Dox distinctly increased the phosphorylation of p38, JNK and ERK MAPKs. Post treatment with CI protein (3 mg/kg body weight, once daily for 4 days), however, reduced Dox-induced oxidative stress and suppressed all these apoptotic events. Histological studies also support the beneficial role of the CI protein in this organ pathophysiology. Combining, results suggest that CI protein might act as a beneficial agent in Dox-induced renal dysfunctions.