Abstract： Objective To assess the effect of PM2.5 on sympathetic innervation and the relationship with cardiac nerve growth factor in healthy rat hearts,identify the ability to the sympathetic nerve reconstruction,and explore the possible arrhythogenic mechanism of PM2.5.Methods Forty healthy SD rats were instilled into trachea with two different solutions twice per week for four weeks:control group with saline and experimental group with PM2.5 25 mg/kg.Then these rats were killed,and biatrial appendages,two ventricular anterior walls were left.Immune cytochemical staining of cardiac nerves was performed using anti-tyrosine hydroxylase antibodies and cardiac nerve growth factor was detected by western blotting.Resuits Compared with the control group,both the density of sympathetic nerves and the expression of cardiac NGF protein in the experimental group were much higher in the left ventricular anterior wall ( P＜0.01 and P＜0.05) and in the right ventricular anterior wall ( P＜0.01 and P＜0.05).Conclusions PM2.5 can induce regional sympathetic hyperinnervation in both ventricular anterior walls in healthy rats by stimulating the NGF protein secretion,and the sympathetic nerve reconstruction effect of PM2.5 was confirmed.