胰岛素样生长因子-1激活大鼠尿道肌卫星细胞促进肌纤维增生

Recombinant human insulin - like growth factor - 1 promotes hyperplasia of muscle fibers of urethral rhabdosphincter in rats by activating satellite cells in situ

目的观察大鼠尿道壁局部注射不同浓度人重组胰岛素样生长因子-1蛋白（rhlGF-1）后，原位肌卫星细胞的激活和增殖。方法雄性成年SD大鼠20只，建立尿道壁局部注射rhlGF-1模型，根据rhlGF-1浓度不同，随机分为生理盐水组、20μg/μl组、50μg／μl组、100μg/μl组，每组5只，生理盐水组作为对照。术后4周，取尿道组织行苏木素-伊红（HE）染色计数新生肌纤维数量，行免疫荧光测定肌卫星细胞分子标记配对核蛋白-7（pax7）及肝细胞生长因子受体（c-Met）蛋白的表达。结果HE染色提示对照组、20μg／μl组、50μg/μl组及100μg/μl组新生肌纤维数分别为（0．82±0．75）、（1．33±0．62）、（2．00±0．74）、（2．67±0．98）个；免疫荧光染色pax7阳性细胞数分别为（27．00±2．65）、（37．87±9．46）、（61．83±11．66）、（64．27±9．28）个；c-Met平均荧光强度分别为（7．41±2．00）、（15．39±4．96）、（21．60±4．26）、（24．04±3．13）；与对照组比较，50μg/μl组及100μg／μl组新生肌纤维数量显著增多（P=0．004、0．000），且pax7阳性细胞数显著增多（P=0．000、0．000），而20μg/μl组两者增加均不明显（P=0．487、0．425）；3个处理组c-Met平均荧光强度均显著高于对照组（P=0．000、0．000、0．000）。结论大鼠尿道壁局部注射人重组胰岛素样生长因子-1能激活原位肌卫星细胞，促进其增殖分化为新生肌纤维，使尿道括约肌增生肥大。

Objective To observe the activation of satellite cells of urethral rhabdosphincter of Sprague - Dawley （SD） rats after local injetion of human recombinant insulin - like growth factor - 1. Methods 20 male SD rats were randomly divided into four groups： control group, and low, medium, and high -dose group （n =5 in each group）. Recombinant human insulinlikegrowth factor- 1 （rhIGF- 1 ） in doses of 20, 50, 100 μg/μl was locally injected into the urethral wall of rats in low, medium, and high - dose rhIGF - 1 group, and the same volume of saline was given to rats in control group. After 4 weeks, the rats were sacrificed. The newly formed myofibers were determined by hematoxylin - eosin （HE） staining and the activation of satellite cells were detected by immunohistochemical staining with satellite cell specific anti - c - Met antibody and anti - pax7 antibody. Results HE staining showed the number of newly formed muscle fibers in control group, 20 μg/μl group, 50 μg/μl group and 100μg/μl group were （0. 82 ± 0. 75 ）, （ 1.33 ± 0. 62 ）, （ 2. 00 ± 0. 74 ）, （ 2. 67 ± 0. 98 ）, respectively; immunofluorescence staining showed the number of pax7 positive muscle fibers were （ 27. 00 ± 2. 65 ） , （ 37.87 ± 9.46 ） , （61.83 ± 11. 66 ） , （ 64. 27 ± 9.28 ） , respectively; the mean fluorescence intensity of c - Met were （7.41 ±2. 00）, （15.39 ±4. 96）, （21.60 ±4. 26）, （24. 04 ±3.13）, respectively. Compared with control group, new muscle fibers increased significantly in 50 μg/μl and 100 μg/μl group （P values were 0. 004 and 0. 000, respectively）. The number of pax7 positive cells also increased significantly in these two groups （P values were 0. 000 and 0. 000, respectively）. However, there was no significant difference between 20 μg/μl group and control group in the number of new muscle fibers and pax7 positive cells （P = 0. 487 and 0. 425, respectively）. The mean fluorescence intensity of c - Met in three treated groups were higher than that in control group （P = 0. 000, 0. 000 and 0. 000, respectively）. Conclusion Local injection of human recombinant insulin - like growth factor - 1 in urethral wall activates muscle satellite cells,promoting it to proliferate and differentiate into new muscle fibers, dosphincter of SD rats.