Effects of low-level laser irradiation on the tissue of rats after myocardial infarction

Abstract

Objective To investigate the influence of low-level laser irradiation (LLLI) on myocardial infarction.Methods In LLLI preconditioning study,vascular endothelial growth factor (VEGF),superoxide dismutase (SOD) and malondialdehyde (MDA) in the infarcted myocardium were evaluated at 1 st h,1 st day and 1 st week after laser irradiation.Results LLLI significantly increased VEGF mRNA and protein expression (4.42 ±2.88 and 2.62 ± 1.83) in the irradiated region after myocardial infarction organization as compared with cntrol group (2.12 ± 0.58 and 1.02 ± 0.41) and sham group (2.42 ± 0.26 and 0.92 ± 0.37,P ＜ 0.05),and there was no significant difference between sham group and control group.After pretreatment for 1 h and 1 day,as compared with control group,the enzymatic activity of SOD in the LLLI infarct myocardial tissue [(0.84 ± 0.43) and (0.92 ± 0.34) U/mg] was significantly increased,and MDA production [(0.56 ±0.31) and (0.50 ± 0.29) nmol/mg] was significantly reduced (P ＜ 0.05).These indicators one week after pretreatment between LLLI group and control group showed no statistically significant difference (P ＞ 0.05).Conclusion LLLI treatment significantly raised VEGF expression and SOD activity in the infarction myocardial tissue,and reduced MDA content,which can improve microenvironment after myocardial infarction,promote cell regeneration and repair after myocardial infarction. Key words: Low-level laser irradiation; Myocardial infarction; Vascular endothelial growth factor; Superoxide dismutase; Malondialdehyde