Comparative Analysis of Antioxidant Activity of Persea americana and Carica papaya against Cadmium Induced Neurotoxicity, Hepatotoxicity and Nephrotoxicity in Rats

Abstract

Cadmium is known to be associated with etiology of different diseases such as itai-itai disease, hepatocellular injury, neurotoxicity, pulmonary edema, cancer, cardiac and neurodegenerative diseases. It is widely reported that cadmium affects the proper functioning of cells by disrupting the cellular redox balance and hence causes apoptosis. The treatment of cadmium toxicity with medicines bring up unwelcoming side effects so there is a need to safely remove cadmium from the body without any harmful effects. The aim of this study was to determine that how cadmium causing malfunctioning of cells could be treated with avocado and papaya fruit juices. This work was focused on elucidating and comparing the effects of avocado and papaya fruit pulp juice on cadmium dependent impairment in memory and spatial learning, level of biomarkers in hepatic and renal tissues, expression of antioxidant enzymes and level of lipid peroxidation caused by cadmium. In order to develop the Cd rat model, CdCl2 (200ppm) was given to rats in drinking water for 7 weeks. After inducing cadmium toxicity for 7 weeks, post treatment with avocado (10%w/v) and papaya (10%w/v) was administered to rats in standard diet. After completing the cadmium post treatment, memory and learning were assessed via morris water maze behavior test. Biochemical tests for liver and kidney biomarkers was observed by liver and kidney function tests. To determine the level of ROS, lipid peroxidation was determined by MDA assay. Gene expression of SOD, CAT and GPx were determined via qRT-PCR. The results of this study elucidated that avocado and papaya fruit juices were successful in reversing the Cd toxicity. The accumulation of cadmium in liver, kidney and hippocampus tissues was found to be reduced after treatment with avocado and papaya. The gene expression of SOD, CAT & GPX were upregulated in avocado and papaya juice post treatment. Moreover, comparative analysis between avocado and papaya fruit juices elucidated that papaya has more active potential in improving the memory and learning, upregulating the antioxidant enzymes expression and reducing lipid peroxidation in liver, kidney and hippocampus. This study suggests that diet containing papaya and avocado can be helpful in the treatment of lethal effects caused by cadmium.