卡那霉素再次耳中毒后听功能变化的实验研究

Functional Recovery of the Avian Cochlea from Poisoning Following Repeated Kanamycin Administration

目的探讨鸡卡那霉素再次耳中毒后听功能的损伤及恢复。 方法将雏鸡于初次耳中毒后 16d开始再次每天肌注卡那霉素 ( 2 0 0mg kg) ,共 10d ,然后于再次药毕后 1、7、10、15d进行ABR检测。 结果首次耳中毒时 ,小鸡听功能损失于药毕时达到极限。停药后即迅速开始恢复 ,药毕 7d时 ,鸡ABR阈值有明显下降 ,药毕 10d时 ,ABR阈值恢复稳定。再次施药 10d完毕时 ,小鸡ABR阈值再次明显升高 ,但其程度较初次损伤时为轻 ( 10 7.14vs116 .32 ) ,药毕后鸡听功能恢复更快 ,再次药毕 7d时鸡ABR阈值已恢复稳定 ,与再次药毕 1d时相比 ,有非常显著性差异 (P <0 .0 1) ,此后鸡ABR阈值未见明显变化。 结论鸡卡那霉素再次耳中毒时 ,其听功能损失程度较初次损伤时为轻 ,恢复速度亦较初次损伤时为快。结果提示鸡卡那霉素初次耳中毒后 ,其基底乳头对卡那霉素的再次损伤具有一定程度的抵抗力。

Objective To study functional recovery of the avian cochlea after a second dose of kanamycin poisoning. Methods Newly Roman hatched chicks for the experiment were treated with kanamycin monosulfate (200mg·kg -1·d -1) again for 10 consecutive days beginning on 16th day after the completion of the initial course. They were tested with ABR 1, 7, 10, 15 days following the first and second dose respectively. Results The most threshold shifts occurred on the chicks at the end of the first 10-day course of kanamycin injection. The hearing function of animals began to recover in a few days and was stable within 10 days after administrated drug. The thresholds measured at 7 days were significantly better than those measured at 1 day after drug cessation(P<0.01), and repeated at 10 days were better than at 7 days(P<0.01). When the animals were treated with kanamycin again for 10 days beginning on the 16th day after completion of the initial course, thresholds shifted, but less than during the first dose period (107.14 vs 116.32,P<0.01). Hearing began to recover in a few days and was stable by the time of 7 days after completion of the second 10-days kanamycin treatment. Conclusion The functional loss of hearing in the avian cochlea is less and recovery is faster following poisoning from the second dose kanamycin. The result suggests that chickens may be less susceptible to the ototoxic effects of repeated kanamycin treatments.