维生素甲酸与哺乳动物听毛细胞再生

Retinoic acid and mammalian auditory hair cell regeneration

近年来研究表明内耳组织中维生素甲酸(RA)浓度可能与毛细胞再生能力有关。本研究以豚鼠为研究对象,采用RA口服给病,探索是否能通过增加耳蜗组织中RA含量来刺激成年活体哺乳动物耳蜗听毛细胞破坏后再生。皮下注射庆大霉素(150mg/d·kg)连续10天以破坏耳蜗毛细胞。自庆大霉素注射开始后的第5天,实验组动物给予全反式RA(1mg/d·kg)。庆大霉素注射停止后的第15、30和60天,取下耳蜗基底膜进行鬼笔环肽-异硫氰酸荧光素(Phalloidin-FITC)染色,计算出毛细胞密度,并对Corti器进行扫描电镜检查。结果发现不同服药时间实验组和对照组动物毛细胞密度无显著差异(P>0.05),扫描电镜下未发现不成熟的再生毛细胞。提示:按本研究的给药剂量及口服给药方式,未发现全反式维生素甲酸能刺激成年豚鼠听毛细胞破坏后再生。本文对可能的原因进行了讨论。

Recent studies showed that high level of retinoic acid(RA)in the inner ear tissue may be related to the observation that those tissues are capable of producing new hair cells. In order to elucldate whether RA can in vivo stimulate the regeneration of auditory hair cells after damage in adult mammals, this study was carried out on the guinea pigs which receive daily subcutaneous injections of gentamicin (150mg/day/kg body weight)for 10 consecutive days to destroy hair cells. From the fifth day of the injections, All-trans RA (1mg/day/kg body weight)was given orally to the guinea pigs of the experimental group untill they were killed, while the control animals were not given RA.On the 15th, 30th and 60th days after treatment, the basilar membranes of Corti’s organs of the guinea pigs were dissected respectively and stained with phalloidin-FITC and the hair cell densities were calculated. The Corti’s organs were examined with scanning electronic microscope(SEM). The differences of the hair cell densities between the experimental and control groups were not significant statistically (P>0.05) at the above-mentioned survival time. No immature regenerative hair cells was recognized by SEM. The results showed that all-trans RA was unable to stimulate hair cell regeneration with this regimen. The reasons for such results were discussed.