histological and immunohistochemical study on the possible protective effect of omega-3 polyunsaturated fatty acids on isoprenaline induced myocardial fibrosis in rats

ABSTRACT

Preclinical and clinical studies have demonstrated that omega-3-polyunsaturated fatty acids [omega-3-PUFAs] play a significant role in the prevention of cardiovascular diseases. This study aimed to investigate the possible protective effect of omega-3-PUFAs on isoprenaline [ISP]-induced myocardial fibrosis. Thirty-two adult male albino rats were divided into five groups. Group I represented the control group [eight rats]. In group II, six rats were given omega-3-PUFAs [40 mg/kg/day] orally for 8 weeks. In group III, six rats were injected subcutaneously with ISP [5 mg/kg/day] for 4 consecutive days and sacrificed 2 days later. In group IV, six rats were injected with ISP [5 mg/kg/day] for 4 consecutive days and sacrificed after 2 weeks. In group V, six rats were given omega-3-PUFAs [40 mg/kg/day] for 8 weeks, following which they were injected with ISP [5 mg/kg/day] for 4 consecutive days, and sacrificed 2 days later. Serum creatine phosphokinase-MB [CPK-MB] was measured. Myocardial sections were subjected to H and E, Masson's trichrome stain, and alpha-smooth muscle actin [alpha-SMA] immunohistochemical stain. Group II showed nonsignificant difference in the mean CPK-MB level compared with the control. Myocardial sections revealed a histological architecture similar to that of the control. The mean area% of collagen and alpha-SMA immunoreactivity was nonsignificant when compared with the control. Group III showed significant increase in mean CPK-MB compared with the control. Myocardial sections showed disorganization, inflammation, exudation, and fibrosis with significant increase in the mean area% of collagen and alpha-SMA immunoreactivity compared with the control. Group IV showed significant increase in mean CPK-MB, area% of collagen, and alpha-SMA immunoreactivity compared with the control, with progression in the myocardial histological alterations. Group V showed significant decrease in the mean CPK-MB with decrease in histological changes, and there was significant decrease in the mean area% of collagen and alpha-SMA immunoreactivity compared with the ISP groups. omega-3-PUFAs exert cardioprotective effects against ISP-induced myocardial fibrosis