二期骨折愈合中骨痂软骨细胞增殖变化的研究

目的 研究骨痂软骨细胞在骨折愈合中增殖变化的规律。方法 采用二 期骨折愈合模型，骨痂组织常规HE染色和细胞周期蛋白（Cyclin D3,Cyclin E,Cyclin A)，5－溴尿嘧啶核苷（Brd U),细胞核增殖抗原（PCNA）免疫染色，观测不同时期骨痂组织形态及其细胞增殖的变化。结果 组织学上可将骨痂组织分为四个区域，即静息区（RZ），增殖区（PZ），成熟区（MZ）和肥大区（HZ）。各区的界面不如发育骨生长板中的清晰，细胞排列较紊乱，规则的软骨细胞柱少见。各区的细胞增殖或因处于不同愈合时期而变化，骨折后第1周以RZ软骨细胞增殖，分化为主；第2，3周PZ软骨细胞增殖活跃，而此时RZ软骨细胞已无明显增殖。第4周时各区软骨细胞增殖活动减弱，细胞以成熟，肥大表现为主。结论 在二期骨折愈合模式中，骨痂软骨细胞增殖变化与骨修复密切相关。

A Study on Proliferation of Chondrocyte in Callus During Second Fracture Healing

Objective To understand the regulation of chondrocyte proliferation in callus. Methods The histological structure of callus was observed and the percent of positive cells of Cylin D 3, Cyclin E, Cyclin A, PCNA and BrdU in callus of 20 male SD rats were caculated in the fracture healing model by HE staining and immunohistochemical staining at 1,2,3 and 4 weeks after fracture. Results The callus under light microscope could be divided into four zones: resting zone(RZ), proliferating zone(PZ), mature zone(MZ) and hypertrophic zone(HZ). The arrangement of chondrocytes in callus was irregular and the boundary between the neighboring zones not as clear as on growth plate. The findings indicated that the proliferation and differentiation of the cells in cambium layer of periosteum and RZ played an important role during fracture healing in the first week; the proliferation of chondrocytes in PZ was very active in the second week, meanwhile the cells in cambium layer became quiet; the proliferating activity of chondrcytes in all these zones became declining and the chondrocytes came to be mature and hypertrophic gradually in the fourth week. Conclusion The proliferating cells in the early stage of fracture healing should have supplied enough chondrocytes, after that time these cells would no longer proliferate; the skeletal repair would be carried out and be accompanied with the proceeding proliferation and differentiation of chondrocytes. After all, the proliferation of chondrocytes in callus is closely related to skeletal repair. Additional characters and elucidation of fracture healing will lay the foundation of subsequent studies aimed at identifying mechanisms for skeletal repair.