失喉返神经支配的人环杓后肌成肌调节因子myogenin表达的变化

Changes of myogenin expression in long-term denervated human posterior cricoarytenoid muscles

目的：观察不同时限失神经状态下人环杓后肌成肌调节因子myogenin的表达变化,为喉神经修复时限的选择奠定基础。方法：取38例喉返神经完全离断患者的环杓后肌标本,按神经离断时限分为4组：失神经6-12个月（n=12）、1-2年（n=10）、2-3年（n=8）及〉3年组（n=8）,另取12例正常环杓后肌标本作为对照,各组患者的年龄、性别比例具有可比性。免疫荧光染色、实时定量PCR法比较各组环杓后肌myogenin蛋白及mRNA的表达。结果：免疫荧光染色结果显示：myoge-nin阳性表达主要定位于失神经3年内的环杓后肌肌细胞核,对照组正常环杓后肌基本无阳性表达;与正常对照组相比,失神经6-12个月组肌细胞核myogenin表达程度及阳性细胞百分比升高,1-2年组表达最高,2-3年组逐渐下降,但仍显著高于对照组（P均〈0.01）,而3年以上组基本无阳性表达,与对照组无显著差异。实时定量PCR结果表明：对照组myogenin mR-NA未表达,失神经1-2年组myogenin mRNA表达水平为6-12个月组的4倍,失神经2-3年组为其64倍,失神经3年以上组仅为其1/2（P均〈0.01）。结论：失喉返神经支配的环杓后肌肌纤维3年内有较大的再生潜力。

Objective：To investigate the change in myogenin expression at different time in long-term denervated human posterior cricoarytenoid muscles（PCAMs）, so as to provide a theoretical basis for timing of reinnervation. Methods： Thirty-eight specimens of denervated human PCAMs were divided into 4 groups according to the period of denervation： 6-12 months denervation group（n= 12） , 1-2 years denervation group （n = 10）, 2-3 years denervation group （n = 8）, and over 3 years denervation group（n=8）. Another 12 specimens of normal PCAMs served as control. The patients in all groups were age- and sex-matched. The expression of myogenin protein and mRNA was studied using immunofluorescence staining and real-time PCR analysis, respectively. Results： Immunofluorescence staining showed that the positive myogenin expression was mainly found in the myonuclei of PCAMs with a denervation period less than 3 years： no positive staining was found in the myonuclei of control group. The expression of myogenin in myonuclei and the ratio of positive cells were up-regulated in the 6-12 month denervation group compared with those in the control group; the expression and the ratio peaked in 1-2 years denervation group and decreased again in the 2-3 years denervation group, but was still significantly higher than those of the control group （all P〈 0.01）. There was hardly any expression of myogenin 3 years after denervation. Results of RT-PCR showed no myogenin mRNA expression in the control group; the expression in 1-2 years, 2-3 years, and more than 3 years denervation groups were 4 times, 64 times, and half that of the 6-12 months denervation group, respectively （all P〈0.05）. Conclusion： It is indicated that there is a potential for muscle regeneration within 3 years of denervation.