供体骨髓细胞在放射损伤肠道中的迁移定植和促修复作用研究

摘要

Objective To explore the engraftment and characteristics of donor bone marrow cells(dBMCs) and their contribution to epithelial regeneration in radiation damaged intestine.Methods Sixty C57BL/6 mice aged 6-8 weeks were exposed to 10 Gy total body irradiation (TBI) and randomly divided into bone marrow transplantation (BMT) group and control group. Survival ratios in two groups were compared. Engraftment of dBMCs in bone marrow and intes-tine was demonstrated by green fluorescent protein(GFP) immunohistochemistry(IHC). Immunofluorescent costaining of GFP with CD45,Sca-1 and Ki67 was employed to study the phenotypes of engrafted dBMCs in intestine. Their contri-bution to intestinal regeneration was determined by HE staining and Brdu analysis.Results Survival ratio in BMT group was 95% on the 14th day. dBMCs migrated into bone marrow and intestine simultaneously. In the intestine, dBMCs firstly appeared at the bottom of lamina propria,then migrated upwards,and finally replaced all the intestinal mesenchy-mal cells. Hematopoietic stem cells (HSCs) appeared in intestine during the early periods. dBMCs alleviated lamina propria edema,promoted proliferation of intestinal stem cells(ISCs),and increased density of intestinal crypts. dBMCs could form epithelial cells in stable chimeric intestine,but not in the early stage.Conclusion dBMCs implant into in-testine in the early time after transplantation,and they promote the regeneration process of radiation damaged intestine.%目的 研究供体骨髓细胞(donor bone marrow cells,dBMCs)在全身放射损伤小鼠肠道内的迁移定植规律和对肠道放射损伤的促修复作用.方法 将60只6~8周龄C57BL/6小鼠进行10 Gy全身照射后随机分为移植组和对照组.比较两组小鼠的存活率,免疫组化分析dBMCs在骨髓和肠道内的定植规律,免疫荧光双染鉴定早期植入肠道内的dBMCs表型.HE染色和Brdu免疫组化分析dBMCs对放射损伤肠道的促修复作用.结果 实验后第14天,移植组小鼠的存活率为95%.dBMCs同时向受体骨髓和肠道迁移定植.移植早期dBMCs首先定植于肠道固有层底部并向上迁移,最终填充全部固有层.早期植入的骨髓细胞中含有Sca-1阳性造血干细胞.dBMCs可缓解放射所致肠黏膜固有层水肿,促进肠道干细胞增殖并增加肠隐窝密度.移植早期dBMCs不形成肠上皮细胞,稳定嵌合后可形成骨髓来源肠上皮细胞.结论 dBMCs在移植后早期即向肠道迁移定植并促进放射所致肠道损伤的修复重建过程.