小鼠毛囊再生与胸腺素β4的促进效应

Thymosin beta4 increases mouse hair regeneration

背景:近年来研究表明,胸腺素β4与毛囊的生长发育和毛发的生长周期有着密切关系,但其作用机制尚不清楚。目的:探讨胸腺素β4通过Wnt信号通路作用于毛囊干细胞对毛囊再生的促进作用。方法:将实验小鼠随机分为低剂量胸腺素β4组、高剂量胸腺素β4组和对照组,使用松香/石蜡混合制剂建立脱毛模型。低剂量胸腺素β4组和高剂量胸腺素β4组给药浓度分别为0.3μg/50μL和3μg/50μL,对照组给予等量PBS,每隔12 h给药1次,均匀涂抹于小鼠脱毛背部。应用大体照相、苏木精-伊红染色、免疫组化及原位杂交技术,观察毛发生长情况,检测不同时间点和不同给药浓度下小鼠毛囊根部细胞β-catenin、LEF-1 mRNA的表达水平。结果与结论:低剂量胸腺素β4组毛发再生速度高于高剂量胸腺素β4组和对照组。苏木精-伊红染色显示在脱毛初期,各组小鼠真皮和皮下脂肪层有一定炎性细胞浸润,9 d时,低剂量胸腺素β4组生长期毛囊数量明显多于高剂量胸腺素β4组和对照组。免疫组织化学和原位杂交结果分别显示β-catenin和LEF-1 mRNA主要表达于毛囊隆突部和外根鞘处细胞的胞浆中,经积分吸光度分析发现低剂量胸腺素β4组阳性细胞数量和染色强度高于高剂量胸腺素β4组和对照组(P<0.05),高剂量胸腺素β4组与对照组间差异无显著性意义。结果显示低剂量的胸腺素β4可以增加部分毛囊外根鞘处细胞内β-catenin和LEF-1 mRNA的表达。胸腺素β4可以促进毛囊再生的机制可能与影响Wnt信号通路有关。

BACKGROUND：Results of recent studies demonstrated the modulation of thymosin β4 on hair cycle and regeneration, but the mechanism of action remains unclear.OBJECTIVE：To investigate the mechanism by which thymosinβ4 increases hair regeneration through Wnt signal pathway.METHODS：After the mouse model of depilation was established using rosin/paraffin mixed agents, the experimental animals were randomly assorted to three different groups, including low-dose, high-dose and control groups, and a dose of 0.3μg/50μL, 3μg/50μL thymosinβ4 and PBS was administered on the depilated backs every 12 hours, respectively. Then photography, hematoxylin-eosin staining, immunohistochemistry and in situ hybridization were applied to observe the growth of hair, and the expressions ofβ-catenin and LEF-1 mRNA in different groups at different time were quantitatively evaluated.RESULTS AND CONCLUSION：The hair growth of the low-dose group was faster than that of the other groups. Hematoxylin-eosin staining demonstrated inflammatory cel s infiltration in the dermis after depilation, and the number of hair fol icles that were in the phase of anagen was much more than the other groups as time went by. Immunohistochemistry ofβ-catenin showed the accumulation of intra-cel ularβ-catenin in the low-dose group at the bulge of fol icles assessed by integrated absorbance analysis （P〈0.05）, so did the in situ hybridization of LEF-1 mRNA. Low-dose thymosinβ4 accelerates hair growth through Wnt signal pathway by elevating the level ofβ-catenin and LEF-1 mRNA.