Investigating the effect of aspalathus linearis as a cardio-protective therapy in isolated rat cardiomyocytes
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Date
2013
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University of Zululand
Abstract
Diabetic cardiomyopathy (DCM) is a common disorder of the heart muscle and it contributes significantly to cardiovascular related deaths in the diabetic population. Excess generation of free radical species due hyperglycaemia has been directly implicated in the pathogenesis of DCM. Current studies focus on therapies to protect a diabetic heart at risk of cardiovascular disease, and also on prolonging lives of diabetic patients. In recent years, the use of Aspalathus linearis (commonly known as rooibos tea), as a therapeutic, has gained popularity worldwide. Aspalathus linearis (rooibos) is rich in antioxidants and may have a cardio-protective effect in combating oxidative stress induced by a diabetic state. However, its role in protection against diabetic-induced cardiomyopathy has not been fully elucidated.
Six month old Wistar rats weighing in the range 350-450 g were used for this study. Rats were divided into a non-diabetic and diabetic group. Diabetes was chemically induced by STZ injection, while rats in the non-diabetic group were treated with citrate buffer. Non-diabetic and diabetic rats were terminated and hearts removed 2 weeks after STZ injection. Cardiomyocytes were isolated and sequentially digested with collagenase before prepared for long term culture. Cultured cardiomyocytes were treated with ARC 61 (1 and 10 μg/ml), vitamin E (50 μg/ml), and n-acetyl cysteine (NAC) (1 mM) for 6 hours, before exposed to either 24 hours of oxidative stress (H2O2 solution) or 2 hours of ischaemia (ischaemic solution). After the pre-determined exposure time, metabolic activity (ATP assay) and relevant bio-assays (apoptosis, H-FABP membrane leakage, intracellular ROS determination and total GSH content) were done to assess the protective effect of rooibos against diabetic-induced cardiomyocytes injury.
Results obtained showed that cardiomyocytes from diabetic hearts were far more susceptible to oxidative damage compared to myocytes obtained from healthy rats. Cardiomyocytes exposed to either H2O2 or an ischaemic solution showed a decrease in metabolic activity and GSH content with a concomitant increase in apoptosis, intracellular ROS and membrane leakage. Pre-treatment with 1 μg/ml of ARC 61 was able to ameliorate this effect.
In conclusion, this study provides evidence that an aqueous extract of ARC61 has a potential cardio-protective effect against diabetic induced-cardiomyopathy in an in vivo cardiomyocyte model.
Description
A dissertation submitted in fullfillment of the requirement for the degree of Masters in Science in the Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa, South Africa, 2013.
Keywords
Diabetic cardiomyopathy, Aspalathus linearis, Cardiovascular related deaths