可吸入颗粒物对大鼠心脏交感神经分布的影响

目的研究可吸入颗粒物对大鼠心脏交感神经分布的影响，明确可吸入颗粒物对心脏自主神经系统是否具有解剖结构的影响。方法24只sD大鼠，均为雄性，随机分为2组（实验组、对照组），每组12只。实验组大鼠按25mg（1ml）／kg体重经气管内缓慢注入颗粒物生理盐水悬液染毒，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，开胸剪取心脏，留取双侧心耳、双心室侧壁及室间隔中部，通过免疫组化方法检测酪氨酸羟化酶（tyrosine hydroxylase，TH）染色阳性的交感神经纤维，其密度等于选区面积的神经纤维数目除以总的测试面积。结果两组大鼠心耳和右室侧壁部位的交感神经分布无明显差异；实验组室间隔和左室侧壁神经分布密度明显高于对照组。结论可吸入颗粒物具有影响大鼠心脏交感神经分布的作用，主要表现为室间隔和左室侧壁神经分布的增多。

Effect of Particulate Matter on Sympathetic Innervation in Healthy Rat Hearts

Objective To assess the effects of particulate matter on sympathetic innervation in healthy rat hearts. Methods Twenty four healthy SD rats were instilled with two different solutions twice per week for four weeks ： saline and 25 mg （ 1 ml） /kg of particulate matter. Particulate matter was collected in glass fiber filters using a high - volume sampler. Then these rats were killed, and only biatrial appendages, two ventricular sidewalls and interventrieular septum were left. Immunocytochemical staining of eardiae nerves was performed using anti - tyrosine hydroxylase （ TH ） antibodies. Nerve fiber density was counted manually for each ease and expressed as the mean number per slice. Results There was no significant difference of the density of TH - positive nerves in the atria among two groups. But in particulate matter group, the density of TH - positive nerves was much higher in interventrieular septum and left ventricular sidewall than in control group. Conclusion Particulate matter can induce regional sympathetic hyperinnervation in interventricular septum and left ventricular sidewall in healthy rats.