复方健耳剂干预庆大霉素耳毒性致豚鼠毛细胞损害的实验研究

Compound Jian'er Mixture Intervened Gentamycin-induced Ototoxic Damage to Hair Cells of Guinea Pigs

目的探讨中药复方健耳剂干预豚鼠庆大霉素(gentamycin,GM)耳毒性致外毛细胞损害的作用及可能机制。方法选择杂色成年豚鼠48只,随机分为正常对照组、GM对照组、复方健耳剂+GM组(简称中药+GM组),每组16只,其中正常对照组按常规饲养至第11天期满;GM对照组按200 mg/(kg·d)剂量,每天分2次连续注射9天,第11天终止饲养;中药+GM组按3.994 g/(kg·d)剂量(1/2人工灌服,1/2自动饮用),预先服用复方健耳剂10天,然后在继续服用中药同时开始注射每天同等剂量GM,连续9天,第11天终止饲养。所有动物期满取出耳蜗,其中每组10只动物用于全耳蜗基底膜铺片,琥珀酸脱氢酶染色,进行耳蜗毛细胞形态学观察,另外每组6只动物,利用Real-time PCR技术检测耳蜗组织硫氧还蛋白(Trx)-1、Trx-2、凋亡信号调节激酶1(apoptosis signal-regulating kinase 1,ASK1)mRNA表达量。结果全耳蜗基底膜检查显示,正常对照组各回三排内、外毛细胞形态正常,数量完整,排列有序;GM对照组各回三排外毛细胞损毁严重,绝大部分细胞出现严重崩解不全,或凋亡缩小,第1回比其他各回损害较重(P<0.01),但内毛细胞仍基本存在;中药+GM组各回三排外毛细胞除少量和散在崩解不全外,大多仍存留可辨,形态如常,内毛细胞仍保持完整,各回外毛细胞损毁状况明显少于GM对照组(P<0.01)。中药+GM组Trx-1、Trx-2 mRNA表达明显高于GM对照组(P<0.01),ASK1 mRNA表达则明显低于GM对照组(P<0.01)。结论一定剂量GM连续使用可造成豚鼠耳蜗外毛细胞严重损害,并以第1回明显,而且以外毛细胞为主要损害靶细胞。复方健耳剂具有防治GM耳毒性外毛细胞损害作用,其机制可能与其调控硫氧还蛋白系统,阻止ASK1依赖的细胞凋亡有关。

Objective To observe the effect and possible mechanism of Compound Jian’er Mixture（ CJM） in intervening gentamycin（ GM）-induced ototoxic damage to hair cells of Guinea pigs. Methods Totally 48 variegated adult guinea pigs were randomly divided into normal control group,GM control group,CJM ＋ GM group [Chinese herbs（ CH） ＋ GM group],16 in each group. Of them,Guinea pigs were conventionally fed until the 11 th day. Those in the GM control groupwere injected by using GM at the daily dose of 200 mg/kg,twice per day for 9 successive days,and terminated at day 11.Those in the CH ＋ GM group took CJM at the daily dose of 3. 994 g/kg（ half for artificial filling and half for automatic drinking） for 10 days in advance,and then received GM injection at equal dose for 9 successive days. And the feeding was terminated at day 11. Cochleas of all expired animals were taken out,and then whole cochlear basilar membrane of 10 animals in each group were used to be micro-dissected out,trimmed and mounted in glycerin on glass slides as flat surface preparations,and their morphology was observed by succinate dehydrogenase staining. Cochleas of the other 6 animals in each group were used for detecting expressions of thioredoxin-1（ Trx-1）,Trx-2,and apoptosis signal-regulating kinase 1（ ASK1） by Realtime PCR. Results The examination of whole cochlear basilar membrane showed that morphology on the three rows of inner and outer hair cells in each turn of the normal control group was normal,the number was complete,and the arrangement was orderly. Three rows of the outer hair cells in each turn of the GM control group were severely damaged. Severe disintegration and incompleteness,or shrunk apoptosis occurred in most of outer hair cells. The first turn was more severely damaged than the other turns（P 〈 0. 01）,but the inner hair cells still basically existed. Most of three rows of the outer hair cells in each turn of the CH ＋ GM group still remained identifiable in normal morphology,except for few amount and incomplete disintegrated cells. The inner hair cells were also kept intact. The damage of outer hair cells in each turn of the CH ＋ GM group was significantly less,as compared with the GM control group（P 〈 0. 01）. The expressions of Trx-1 and Trx-2 in cochlear tissue were significantly higher in the CH ＋ GM group than in the GM control group（P 〈 0. 01）. Furthermore,the ASK1 expression was significantly lower in the CH ＋ GM group than in the GM control group（P 〈 0. 01）. Conclusions Continuous use of some certain dose of GM could cause severe damage of Guinea pigs’ cochlear outer hair cells. The damage to the first turn was more obviously seen. Moreover,the outer hair cells were main damage target cells. CJM showed significant prevention and treatment for GM-induced damage of outer hair cells. Its protective mechanisms might be related to regulating thioredoxin system,impeding ASK1-mediated apoptosis.