PM2.5对大鼠心脏交感神经分布的影响及其与心肌神经生长因子表达的关系

Effect of PM2. 5 on sympathetic innervation by stimulating the secretion of cardiac nerve growthfactor in healthy rat hearts

目的研究可吸入颗粒物PM2.5对大鼠心脏交感神经分布的影响及其与心肌神经生长因子表达的关系，明确PM2.5是否具有致交感神经重构作用，探讨PM2.5致心律失常的可能机制。方法40只SD雄性大鼠，随机分为对照组和实验组，每组20只。实验组大鼠按25mg／kg剂量经气管内缓慢注入颗粒物悬液染毒，每周染毒2次，连续染毒4周；对照组以生理盐水代替颗粒物悬液；两组大鼠于末次染毒后次日处死，开胸留取双侧心耳和双心室前壁，通过免疫组化方法检测酪氨酸羟化酶染色阳性的交感神经纤维分布密度，同时采用蛋白免疫印迹法检测心肌神经生长因子（NGF）蛋白表达。结果与对照组比较，实验组大鼠吸人PM2.5后，心脏左室前壁和右室前壁交感神经分布密度明显升高（P〈0．01和P〈0．05），心肌NGF蛋白表达明显增加（P〈0．01和P〈0．05），两者密切相关。结论PM2.5能增加大鼠左右心室心肌细胞合成和分泌NGF蛋白，从而导致心室交感神经分布密度增加，证实具有致交感神经重构作用。

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 recon- strnction, and explore the possible arrhythogenic mechanism ofPM2.5 Methods Forty healthy SD rats were instilled into trachea with two different solutions twice per week for four weeks： control group with sa- line 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. Re- suits Compared with the control group, both the density of sympathetic nerves and the expression of cardi- ac NGF protein in the experimental group were much higher in the left ventricular anterior wall （ P 〈8. 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 stimula- ting the NGF protein secretion, and the sympathetic nerve reconstruction effect of PM2.5 was confirmed.