骨髓间充质干细胞联合RANK-Fc局部注射促进糖尿病大鼠骨折愈合的可能机制

A possible mechanism to promote fracture healing via injection of locally mesenchymal stem cells and RANK-Fc in GK diabetic rats

目的检测促炎因子肿瘤坏死因子-α(TNF-α)和抗炎因子白介素-10(IL-10)在骨髓间充质干细胞(MSC)联合RANK-Fc促进GK糖尿病大鼠骨折愈合过程骨组织中的表达,探讨促炎—抗炎平衡在此过程中的作用。方法 7—8周龄SPF级雄性GK大鼠40只,喂养高脂饲料糖尿病造模。造模成功后(随机血糖≥11.1 mmol/L)选取大鼠左侧肢体,人为造成股骨中段开放性骨折并给与克氏针复位内固定,随机分为4组(n=10只),其中3组分别在骨折周围肌肉软组织注射培养浓缩的骨髓MSC、RANK-Fc、骨髓MSC和RANK-Fc混合液,于实验后第12周分别行X线摄片、取骨折处骨组织检测TNF-α和IL-10的表达。结果骨折内固定术后第12周摄片对照组骨愈合不佳,断端骨皮质不连续,骨密度较低;MSC组、RANK-Fc组、MSC+RANK-Fc组可见骨密度较对照组高,骨痂生长,连续爬行,骨皮质连续,MSC+RANK-Fc组愈合情况最佳;Western blot结果:对照组促炎因子TNF-α明显高于MSC组、RANK-Fc组、MSC+RANK-Fc组,而抗炎因子IL-10明显低于其他3组(P<0.05)。结论骨髓MSC联合RANK-Fc局部注射可以抑制GK糖尿病大鼠骨折内固定术后机体的炎症反应,从而促进骨折的愈合。

Objective To study the role of inflammation imbalance on mesenchymal stem cells and RANK-Fc（antagonisten of RANKL） promoting fracture healing in GK diabetic rats by detecting the expressions of tumor necrosis factor-α（TNF-α） and interleukin-10（IL-10）. Methods GK diabetic rats were induced by feeding them with high-fat diet（random blood sugar ≥ 11.1 mmol/L）. The fractures were fixed with Kirschner wire after the left thigh-bone of rats were exploded and sawed off, then the concentrated stem cells and RANK-Fc were injected into the local areas of the fractures. Bone tissue specimens were collected for detecting the expression of TNF-α and IL-10 during the twelfth week. The fracture healing was evaluated with X-ray.Results The expressions of TNF-α were much higher in the control group than in MSC, RANK-Fc and RANK-Fc＋MSC group; however, the levels of IL-10 were lower in the control group（P〈0.05）. The osteotylus formation was more obvious and the bone mineral density more homogeneous in the experimental group.Conclusion It can inhibit the inflammatory reaction to inject concentrated mesenchymal stem cells and RANK-Fc into the local area of the fracture in the GK diabetic rats, thus promoting the fracture healing in the experimental group.