Brief introduction: Myocardial infarction (MI) is a common manifestation of certain cardiac diseases where oxidative stress and fibrosis aggravate the condition markedly.
Main objective of the study: Investigation of L-carnitine's cardioprotective roles and mechanism of action in a rat model of MI.
Methods: To develop a MI animal model, Isoproterenol (ISO) was administered in male Long Evans rats where animals were divided into five groups (six rats/group). The oxidative stress and antioxidant enzyme activities were determined by different biochemical tests. The real-time PCR was performed to determine the expression of TNF-α and Il-1β. Histopathological observations by hematoxylin-eosin and Masson trichrome were made to observe the tissue damage and fibrosis in heart and kidney.
Significant findings from the study: The ISO-treated rats showed increased levels of troponin I and lipid peroxidation and lower antioxidant enzyme activity in heart and kidney tissues. The levels of TNF-α and IL-1β were also increased in ISO-rats. Co-administration of L-carnitine with ISO reversed all these parameters. The elevated levels of uric acid and creatinine kinase and ALP, AST and ALT activities in ISO-rats were also significantly reduced by L-carnitine administration. L-carnitine markedly decreased the infiltration of inflammatory cells and improved the tissue architecture in heart and kidney. Control animals did not show any appreciable response upon L-carnitine administration.
Relevant contribution to knowledge: These results suggest that L-carnitine plays a defensive role against cardiac and renal damage in ISO-treated MI rat model via suppressing oxidative stress and increasing antioxidant enzyme functions through inhibition of TNF-α and IL-1β.
Keywords: Cardiac fibrosis; Inflammation; Isoproterenol; L-carnitine; Oxidative stress.
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