糖尿病大鼠骨折愈合早期局部骨痂组织中Ⅰ型胶原纤维表达和骨密度的变化

背景：糖尿病患者骨折愈合过程中局部骨痂形成较差，成骨细胞增殖能力下降，骨折延迟愈合或者不愈合，而Ⅰ型胶原纤维和钙质成分是骨痂的主要成分。目的：观察糖尿病大鼠骨折愈合早期过程中骨痂组织中Ⅰ型胶原纤维含量和骨密度的变化，分析糖尿病大鼠骨折愈合过程中骨折延迟愈合，或者不愈合的原因。方法：10只腹腔内注射链脲佐菌素破坏胰岛细胞诱导为糖尿病大鼠，10只为正常对照大鼠，腹腔内注射等容量生理盐水。2组大鼠均造成右胫骨斜形骨折，于伤后第1，2，4，6周取骨痂组织进行检测。结果与结论：正常对照组X射线片显示骨痂生成量多，骨折愈合程度明显优于模型对照组(P < 0.01)，各组Ⅰ型胶原纤维表达均呈上升趋势，在第2周达到峰值，第4周下降，至第6周进一步下降。模型对照组骨痂中Ⅰ型胶原纤维表达和骨密度升高幅度明显低于正常对照组(P < 0.01)。提示糖尿病大鼠骨折愈合过程中较正常大鼠骨痂生成下降，骨痂中Ⅰ型胶原纤维表达和骨密度升高幅度同步下降。

Local expression of type I collagen fibers and changes of bone mineral density in callus tissues of diabetic rats during early fracture healing

BACKGROUND:Studies have shown that local callus formation is poor in diabetic patients during fracture healing process, and the proliferation ability of osteoblasts decrease, resulting in delayed union or nonunion. Type I collagen fibers and calcium are the main components of the callus.OBJECTIVE:To observe the local expression of type I collagen fibers and changes of bone mineral density in callus tissues of diabetic rats during early fracture healing so as to analyze the reasons for delayed union or nonunion.METHODS:Ten rats received intraperitoneal injection of streptozotocin to induce diabetic models, and another 10 rats served as controls undergoing intraperitoneal injection of an equal volume of normal saline. Oblique fracture of the right tibia was induced in all the rats. Callus was taken for measurement at 1, 2, 4, 6 weeks after injury.RESULTS AND CONCLUSION:In the control group, X-ray displayed callus formation, and fracture healing was significantly better than that in the model group (P < 0.01). In these two groups, the expression of type I collagen fibers showed an upward trend, reached its peak at week 2, decreased at week 4 and further declined from week 6 on. In the model group, the expression of type I collagen fibers and bone mineral density was increased but lower than those in the control group (P < 0.01). These findings indicated that the callus formation decreased during fracture healing in diabetic rats, and the increased range of type I collagen fibers and bone mineral density in the callus had a synchronous decline.