内耳免疫反应中细胞凋亡及Bcl-2与Bax的表达

目的 研究内耳免疫反应时细胞凋亡以及Bcl 2和Bax的表达情况，探讨自身免疫性内耳病发病机制。方法 选用健康SD大鼠60只，随机分成实验组30只（皮下注射Ⅱ型胶原与弗式佐剂），佐剂组15只（皮下注射弗式佐剂），对照组15只（予等量生理盐水），免疫后进行畸变产物耳声发射（DPOAE）检测，扫描电镜形态学观察，DNA末端转移酶介导的缺口末端标记法（TUNEL）检测细胞凋亡及免疫组化检测Bcl-2和Bax的表达。结果 实验组DPOAE幅值下降（P<0.05），部分毛细胞纤毛排列紊乱、簇状缺失， Corti器、血管纹和螺旋神经节可见TUNEL阳性染色, 且Bax/ Bcl-2表达比值上调，而对照组和佐剂组未见明显改变。结论 内耳免疫反应可诱导细胞凋亡发生, Bcl 2和Bax蛋白在其中起了重要调节作用。

Apoptosis and expression of bcl-2 and bax in inner ear immune response

Objective To investigate whether apoptosis is one of the mechanism in the immune response of the inner ear and to detect expression of Bcl-2 and Bax in inner ears. Methods Sixty healthy SD rats were divided into the experimental group(30 systematically injected with type Ⅱcollagen and freund adjuvant), the adjuvant group(15 injected with freund adjuvant) and the control group(15 injected with the same volume of saline). DPOAE was performed and scanning electron microscopy was applied to evaluate cochlear morphology．The TUNEL method was used to detect apoptotic cells in inner ear immume response. The immunohistochemical method was applied to detect expression of Bcl-2 and Bax. Results DPOAE amplitudes decreased and the cilia of hair cells mostly disappeared with spaces between hair cells in the experimental group compared with the adjuvant group and control group(P<0.05).TUNEL-positive cells could be detected in the corti organ, stria vascularis and spiral ganglion cells and the ratio of Bcl-2/Bax increased in the experimental group. Conclusions These findings suggest apoptosis is involved in the pathogenesis of the immune response of inner ears and Bcl-2 and Bax play critical roles in it.