背景:以往一直认为损伤的毛细胞不具有修复能力.近年研究表明,哺乳动物前庭毛细胞破坏后也保持一定的修复能力.那么,哺乳类动物耳蜗毛细胞破坏后是否具有再生能力?目的:应用扫描电镜技术并结合听性脑干反应测试,观察庆大霉素中毒后不同时间豚鼠耳蜗毛细胞情况和听性脑干反应阈值变化,以观察哺乳动物耳蜗毛细胞受损后能否再生.设计:随机对照动物实验.单位:沈阳医学院生理教研室.材料:实验于2001-11/2002-05在中国医科大学听力研究室完成.选用清洁级耳郭反射灵敏的健康成年白色红目豚鼠60只,随机分为庆大霉素组、正常对照组,每组30只.方法:庆大霉素组每日腹腔注射庆大霉素100mg/kg.正常对照组每日腹腔注射与庆大霉素等量的生理盐水2.5 mL/kg,各组皆连续用药10 d.每日测量体质量调整药量.在用药前和停药后1,3,30 d分别检测听性脑干反应阈值;停药处死后应用扫描电镜技术观察各组豚鼠耳蜗毛细胞情况.主要观察指标:①听性脑干反应阈值.②庆大霉素中毒后不同时间豚鼠耳蜗毛细胞变化.结果:实验动物60只中途无脱落,全部进入结果分析.①庆大霉素组停药后1,3,30 d其听性脑干反阈值显著高于正常对照组,差异有显著性[(38.00±3.75),(2.22±3.63)dB nHL,t=30.651,P＜0.001];[(39.09±4.22),(2.50±3.54)dB nHL,t=29.708,P＜0.001];[(14.50±3.69),(1.50±2.42)dB nHL,t=13.175,P＜0.001].30 d时听性脑干反应阈值有明显恢复,但未达到正常水平.②庆大霉素组停药后1 d豚鼠耳蜗第二转外毛细胞静纤毛显示融合、扭曲、倒伏、缺失或残缺不全等病理改变,尤其是第三排外毛细胞更为严重,且内毛细胞静纤毛外侧有囊状突出物;停药后3 d豚鼠耳蜗第二转外毛细胞静纤毛融合、缺失、倒伏等病理改变仍然存在,内毛细胞静纤毛仍有倒伏现象,而其外侧囊状突出物减少;停药后30 d豚鼠耳蜗第二转外毛细胞静纤毛融合、缺失、倒伏等病理改变,明显弱于庆大霉素停药1 d和3 d,同时耳蜗第三转有新生的静纤毛出现.结论:庆大霉素耳中毒后豚鼠耳蜗毛细胞损伤后存活30 d者其耳蜗毛细胞形态上有所恢复,且听性脑干反应阈值也有一定程度的恢复,说明庆大霉素耳中毒后豚鼠耳蜗毛细胞具有再生修复能力.庆大霉素损伤后的毛细胞可以再生.
揹景:以往一直認為損傷的毛細胞不具有脩複能力.近年研究錶明,哺乳動物前庭毛細胞破壞後也保持一定的脩複能力.那麽,哺乳類動物耳蝸毛細胞破壞後是否具有再生能力?目的:應用掃描電鏡技術併結閤聽性腦榦反應測試,觀察慶大黴素中毒後不同時間豚鼠耳蝸毛細胞情況和聽性腦榦反應閾值變化,以觀察哺乳動物耳蝸毛細胞受損後能否再生.設計:隨機對照動物實驗.單位:瀋暘醫學院生理教研室.材料:實驗于2001-11/2002-05在中國醫科大學聽力研究室完成.選用清潔級耳郭反射靈敏的健康成年白色紅目豚鼠60隻,隨機分為慶大黴素組、正常對照組,每組30隻.方法:慶大黴素組每日腹腔註射慶大黴素100mg/kg.正常對照組每日腹腔註射與慶大黴素等量的生理鹽水2.5 mL/kg,各組皆連續用藥10 d.每日測量體質量調整藥量.在用藥前和停藥後1,3,30 d分彆檢測聽性腦榦反應閾值;停藥處死後應用掃描電鏡技術觀察各組豚鼠耳蝸毛細胞情況.主要觀察指標:①聽性腦榦反應閾值.②慶大黴素中毒後不同時間豚鼠耳蝸毛細胞變化.結果:實驗動物60隻中途無脫落,全部進入結果分析.①慶大黴素組停藥後1,3,30 d其聽性腦榦反閾值顯著高于正常對照組,差異有顯著性[(38.00±3.75),(2.22±3.63)dB nHL,t=30.651,P＜0.001];[(39.09±4.22),(2.50±3.54)dB nHL,t=29.708,P＜0.001];[(14.50±3.69),(1.50±2.42)dB nHL,t=13.175,P＜0.001].30 d時聽性腦榦反應閾值有明顯恢複,但未達到正常水平.②慶大黴素組停藥後1 d豚鼠耳蝸第二轉外毛細胞靜纖毛顯示融閤、扭麯、倒伏、缺失或殘缺不全等病理改變,尤其是第三排外毛細胞更為嚴重,且內毛細胞靜纖毛外側有囊狀突齣物;停藥後3 d豚鼠耳蝸第二轉外毛細胞靜纖毛融閤、缺失、倒伏等病理改變仍然存在,內毛細胞靜纖毛仍有倒伏現象,而其外側囊狀突齣物減少;停藥後30 d豚鼠耳蝸第二轉外毛細胞靜纖毛融閤、缺失、倒伏等病理改變,明顯弱于慶大黴素停藥1 d和3 d,同時耳蝸第三轉有新生的靜纖毛齣現.結論:慶大黴素耳中毒後豚鼠耳蝸毛細胞損傷後存活30 d者其耳蝸毛細胞形態上有所恢複,且聽性腦榦反應閾值也有一定程度的恢複,說明慶大黴素耳中毒後豚鼠耳蝸毛細胞具有再生脩複能力.慶大黴素損傷後的毛細胞可以再生.
배경:이왕일직인위손상적모세포불구유수복능력.근년연구표명,포유동물전정모세포파배후야보지일정적수복능력.나요,포유류동물이와모세포파배후시부구유재생능력?목적:응용소묘전경기술병결합은성뇌간반응측시,관찰경대매소중독후불동시간돈서이와모세포정황화은성뇌간반응역치변화,이관찰포유동물이와모세포수손후능부재생.설계:수궤대조동물실험.단위:침양의학원생리교연실.재료:실험우2001-11/2002-05재중국의과대학은력연구실완성.선용청길급이곽반사령민적건강성년백색홍목돈서60지,수궤분위경대매소조、정상대조조,매조30지.방법:경대매소조매일복강주사경대매소100mg/kg.정상대조조매일복강주사여경대매소등량적생리염수2.5 mL/kg,각조개련속용약10 d.매일측량체질량조정약량.재용약전화정약후1,3,30 d분별검측은성뇌간반응역치;정약처사후응용소묘전경기술관찰각조돈서이와모세포정황.주요관찰지표:①은성뇌간반응역치.②경대매소중독후불동시간돈서이와모세포변화.결과:실험동물60지중도무탈락,전부진입결과분석.①경대매소조정약후1,3,30 d기은성뇌간반역치현저고우정상대조조,차이유현저성[(38.00±3.75),(2.22±3.63)dB nHL,t=30.651,P＜0.001];[(39.09±4.22),(2.50±3.54)dB nHL,t=29.708,P＜0.001];[(14.50±3.69),(1.50±2.42)dB nHL,t=13.175,P＜0.001].30 d시은성뇌간반응역치유명현회복,단미체도정상수평.②경대매소조정약후1 d돈서이와제이전외모세포정섬모현시융합、뉴곡、도복、결실혹잔결불전등병리개변,우기시제삼배외모세포경위엄중,차내모세포정섬모외측유낭상돌출물;정약후3 d돈서이와제이전외모세포정섬모융합、결실、도복등병리개변잉연존재,내모세포정섬모잉유도복현상,이기외측낭상돌출물감소;정약후30 d돈서이와제이전외모세포정섬모융합、결실、도복등병리개변,명현약우경대매소정약1 d화3 d,동시이와제삼전유신생적정섬모출현.결론:경대매소이중독후돈서이와모세포손상후존활30 d자기이와모세포형태상유소회복,차은성뇌간반응역치야유일정정도적회복,설명경대매소이중독후돈서이와모세포구유재생수복능력.경대매소손상후적모세포가이재생.
BACKGROUND: Formerly, it was thought that the damaged hair cells could not have the repair ability. Recent studies demonstrate that mammal vestibule hair cells also possess certain repair ability after being destroyed.Then, whether mammalia animal cochlea hair cells possess regenerative ability after being destroyed is disputed.OBJECTIVE: To observe cochlear hair cells condition and threshold value change of auditory brainstem response (ABR) at different time following gentamicin ototoxicity by using scanning electron microscope (SEM) technique combined with ABR test, so as to investigate whether cochlear hair cells of mammals can be regenerated after being injured.DESIGN: A randomized and controlled animal experiment.SETTING: Department of Physiology, Shenyang Medical College.MATERIALS: This experiment was carried out at the Hearing Research Room of China Medical University from November 2001 to May 2002. Totally 60 healthy adult white Guinea pigs, with red eyes and sensitive auricle reflex, of clean degree, were used and randomly divided into gentamicin group and normal control group with 30 guinea pigs in each one.METHODS: 100 mg/kg gentamicin was intraperitoneally daily injected into the guinea pigs, serving as gentamicin group. Same volume of normal saline (2.5 mL/kg) was intraperitoneally daily injected into the guinea pigs,serving as normal control group. All the guinea pigs were given medication for 10 successive days. Threshold value of ABR was detected respectively pre-operatively and at the 1st, 3rd, 30th days postoperatively; after withdrawal and execution, scanning electron microscope was used to observe cochlear hair cells of guinea pigs in each group.MAIN OUTCOME MEASURES: ① Threshold value of ABR. ②Cochlear hair cell change of guinea pigs at different time following gentamicin ototoxicity.RESULTS: All the 60 experimental animals entered the stage of result analysis with no loss in the midway. ①At 1,3 and 30 days after withdrawal of gentamicin, threshold value of ABR was significantly higher as compared with normal control group, with significant difference [(38.00±3.75), (2.22 ±3.63) dB nHL,t=30.651, P ＜ 0.001];[(39.09±4.22), (2.50±3.54) dB nHL, t=29.708, P ＜ 0.001];[(14.50±3.69), (1.50±2.42) dB nHL,t =13.175, P ＜ 0.001]. Threshold value of ABR recovered obviously on day 30, but did not reach the normal level. ②On the first day after withdrawal of gentamicin , stereocilium of hair cells in second turn of cochlea of guinea pigs presented fusion, distortion, lodging, loss or incompetence and other pathological changes , especially severe in the third turn , also cystic form protrutions appeared outside the stereocilium of inner hair cell; On day 3 after withdrawal of gentamicin, stereocilium of outer hair cells in the second turn of cochlea of guinea pigs still presented fusion, loss, lodging and other pathological changes. Stereocilium of inner hair cell still showed lodging,but the outside cystic form protrutions decreased; On day 30 after withdrawal of gentamicin, stereocilium of outer hair cells in the second turn of cochlea presented fusion, loss , lodging and other pathological change ,which were obviously weaker than those on the 1st day and 3rd day after withdrawal of gentamicin , and at the same time , new born stereocilium appeared in the third turn of cochlea.CONCLUSION: Cochlear hair cell morphology recovery appears in those which survive for 30 days after cochlear hair cells of guinea pigs are damaged following gentamicin ototoxicity, and threshold value of ABR also recovers to some extent, suggesting that cochlear hair cells possess regenerative and repair ability following gentamicin ototoxicity. Hair cells after gentamicin-induced cochlear damage possess regenerative ability.
