8 Hz130dB次声作用后鼠脑mGluR1〆的改变

Alterations of mGluR1〆 in various brain nucleus after infrasonic damage in rats

目的 探讨 8 Hz 130 d B次声作用后代谢性谷氨酸受体 1α(m Glu R1α)在鼠脑各核团中表达的改变及其意义 .方法 SD大鼠 40只随机分为对照组及次声作用 1,7和 14次共 4组 ,次声作用组用 8Hz 130 d B的次声按规定次数作用 ,每次 2 h.多聚甲醛心脏灌注固定鼠脑 ,免疫细胞化学染色 ,光镜下观察 m Glu R1α在各核团表达改变 .结果 次声作用 1次组 ,大多数核团 m Glu R1α阳性神经元表达增多 ;至 7次组免疫反应阳性神经元数目增多显著 ,细胞淡染 ,中间低密度 ,类空泡样变 .核团内免疫阳性纤维同时增多 ,染色加深 ;14次组各核团阳性神经元减少至或低于正常水平 .结论 次声作用可引起脑内多数各核团神经元 m Glu R1α表达增高 ,提示 m Glu R1α是介导谷氨酸兴奋性毒性 。

AIM To study the alterations of mGluR1α in various brain nuclei after infrasonic damage in rats so as to probe into the function of mGluR1α in infrasonic damage. ME THODS Forty SD rats were randomized into four groups: control group and one time, 7 time, 14 time infrasonic damage groups. Rats were exposed to 8 Hz 130 dB infrasound as designed, 2 h each time. Paraformldehyde liquid was used for the brain fixation through intracardiac perfusion. mGluR1α was detected by immunohistochemistry method. The alterations of mGluR1α in nucleus were observed under light microscope. RESULTS The expression of mGluR1α positive neurons increased in major nucleus after infrasonic damage in 1 time group and was most obvious in 7 time group. The neurons were lightly stained with low density in the middle, and positive fibers with dark stain in nucleus increased, while mGluR1α positive neurons in 14 time group decreased or reached normal level. CONCLUSION Infrasound can induce mGluR1α positive neurons expression to increase. The change of mGluR1α activity can mediate glutamate excitotoxicity and is one of the major factors leading to neuronal injury after the effect of infrasound.