微创性损伤诱发晶状体上皮向平滑肌样细胞分化的探讨

Epithelial-smooth muscle-like cell differentiation of lens epithelium after micro-trauma of mouse lens

目的建立微创性白内障动物模型,探讨晶状体上皮向平滑肌样细胞的分化。方法4～6周C57BL/6j小鼠24只,随机分为实验组和对照组。实验组采用微创穿破晶状体后囊膜,注入10μLPBS;对照组仅玻璃体腔内注射等量的PBS,术后行眼部检查及裂隙灯照相。术后第3、7、14、28d取眼球,行组织病理学观察及平滑肌肌动蛋白(SMA)、波形纤维蛋白(Vim)免疫组织化学染色。结果术后1～3d,实验组11只眼晶状体相继发生不同程度的白色混浊。混浊眼球术后3d,组织病理学观察示晶状体赤道区上皮开始沿创口处爬行;7d后囊下梭形细胞层增多3～6层,细胞体积增大。14～28d梭形细胞层数基本保持不变。免疫组织化学染色显示增生的梭形细胞SMA强阳性,Vim阴性。对照组均无上述变化。结论微创性损伤晶状体出现白内障,能诱发晶状体上皮向平滑肌样细胞分化。

Objective Previous studies showed that epithelial-mesenchymal transition（EMT） play an important role not only in development of embryo, hut also in healing of wound, fibrosis, invasion and metastasis of tumor cells. Further studies demonstrated that EMT was involved in after-cataract and alkali burn-induced cataract. This study tried to investigate the epithelial-smooth muscle-like cell differentiation of lens epithelium after micro-trauma of mouse lens. Methods Twenty four C57BL/6j postnatal mice aged 4 - 6 weeks were divided into experiment group and control group averagely and randomly. The posterior lens capsule of the right eyes of mice were penetrated using 10μL micro syringe needle followed the intra-lens injection of PBS in experiment group,and equal amount of PBS was intravitreously injection without any posterior capsule injury in the eyes of control mice. Clinical changes were assessed by slit-lamp examination and photograph after the operation. The eyeballs of mice were enucleated at 3,7,14 and 28 days after operation,respectively. Both HE and immunohistochemistry were used to detect the pathological changes of mice lens. Results Postoperative 1 to 3 days,lens of 11 mice in experiment group appeared to he alha turbid to different degree and then developed into high-density chinaware gradually. HE staining showed that on postoperative day 1 ,the lens epithelium crawled to posterior sub-capsule from the equator of lens and the shape of the cells changed from cuhoidal to spindle-shape during the immigration. On operative day 3 ,the spindle-shape cells enlarged and proliferated from monolayer to muhilayer （3 - 6 layers） , and some of which lined in bunchs, lmmunohistochemistry showed that these spindle-shape cells appeared positive response for smooth muscle actin（SMA） strongly and negative response for vimentin（Vim）. No similar change was observed in the lens in control group. Conclusion Micro-trauma of mouse lens can induce the differentiation of lens epithelium into lens epithelial-smooth muscle-like cell.