钙敏感钾通道参与川芎嗪拮抗链霉素耳毒性作用及可能机制

Calcium sensitive potassium channels involved in the antagonism effect of tetramethypyrazine on streptomycin ototoxicity

目的探讨川芎嗪拮抗链霉素耳毒性损伤机制。方法将30只豚鼠随机分为三组,对照组(每日腹腔注射生理盐水2.5 ml/kg),链霉素组(SM组,每日腹腔注射硫酸链霉素450mg/kg,同时在对侧腹腔注射生理盐水2.5 ml/kg),川芎嗪+链霉素组(TMP+SM组,每日腹腔注射川芎嗪注射液100mg/kg,同时在对侧腹腔注射硫酸链霉素450 mg/kg)。各组皆连续注射10 d,并于实验前后进行听性脑干电位(ABR)监测。10 d后处死并制备耳蜗标本,进行耳蜗基底膜铺片、透射电镜观察以及BKCa免疫组化染色。结果链霉素组ABR阈值明显高于对照组,而TMP+SM组明显低于链霉素组(P<0.01)。SM组外毛细胞(OHC)胞膜有断裂,细胞质溶解,线粒体数目减少、形态模糊、部分嵴缺损,细胞核有异染色质边集。TMP+SM组OHC损伤程度显著轻于SM组。SM组BKCa表达水平明显比对照组低,而TMP+SM组明显高于SM组。结论川芎嗪拮抗链霉素耳毒性损伤可能与上调BKCa表达相关。

Objective To study the possible mechanism of tetramethypyrazine on anti-streptomycin ototoxicity in guinea pig. Methods 30 guinea pigs were randomly divided into three groups（n=10 averagely）, control group（normal saline 2.5 ml/kg, i.p.）, streptomycin group（streptomycin 450 mg/kg with normal saline 2.5 ml/kg, i.p.）, tetramethypyrazine ＋streptomycin group（tetramethypyrazine 100mg/kg and streptomycin 450 mg/kg, i.p.）, all continued for 10 days. Auditory brainstem response（ABR） was measured. The cochlea specimens were prepared for cochlear basement membrane staining, the ultrastructure of outer hair cells was observed by transmission electron microscope, BKCa expression was studied by immunohistochemical staining. Results ABR threshold value was increased in streptomycin group than in control group（P〈0.01）, but lower in tetramethypyrazine＋streptomycin group than in streptomycin group（P〈0.01）.Tetramethypyrazine promoted the morphological repair of the damaged outer hair cells. The expression level of BKCa in cochlea was decreased in streptomycin group than in control, but increased in tetramethypyrazine group than in streptomycin group. Conclusion The antagonism effect of tetramethypyrazine on streptomycin ototoxicity might be related to upregulation of BKCa expression in cochlea.