Objective:To study and understand the influence of diabetes on proliferation and apoptosis of chondrocyte in growth plate. Methods: The rat diabetic model (STZ) was established. All experimental rats were randomly divided into normal groups: C0N1, C0N2; diabetic groups: DM1 and DM2. The tissues were observed by HE staining and toluidine blue staining. Proliferating cell nuclear antigen (PCNA) and TUNEL expressions were examined by S-P method. The expressions of melatonin receptors (MT1, MT2) with immunohistochemistry were observed, and image analysis and statistics analysis were performed. Results: The thickness and the density of cell pillar of growth plate of the 3-month diabetic rats in the diabetic groups were obviously lower than those in the control group. The PCNA expression was positive but decreased in the experimental proliferative and hypertrophic zone, the TUNEL expression increased in the experimental proliferative zone. In the experimental group, the galactosidase expression was increased everywhere. The level of decorin decreased in comparison with the control group. The expression of MT1, MT2 was increased in growth plate and the mineralized zones and subchondral bone. Conclusion: The proliferation and apoptosis of chondrocytes in growth plate in diabetic rats can increase synchronism. The proliferative activity of chondrocytes attenuated in an advanced stage. The apoptosis labeling of the proliferative zone mainly on the growth and degradation of cartilage by diabetes turn to a leading role. Extracellular matrix degradated.%目的:探讨糖尿病大鼠生长板软骨细胞增殖分化情况以及褪黑素对软骨内成骨的影响.方法:建立速发型链脲佐菌素糖尿病大鼠模型,随机分为正常1月组、3月组、糖尿病1月组、3月组.采用H-E染色、增殖核抗原(PCNA)免疫组织化学显色观察软骨细胞的增殖情况.原位末端标记法(TUNEL)、衰老相关半乳糖苷试剂盒检测软骨细胞的衰老与凋亡.甲苯胺蓝染色显示软骨基质代谢,免疫组织化学显色检测褪黑素受体(MT1、MT2)的表达.结果:糖尿病1月组与正常组相比无变化.糖尿病3月组生长板软骨细胞柱密度均明显小于正常组；PCNA阳性表达在增殖层和肥大层降低,TUNEL阳性表达、半乳糖苷酶在增殖层明显增多,蛋白聚糖水平低于正常组.MT1、MT2在生长板及钙化区组织表达减弱.结论:糖尿病大鼠软骨细胞的增殖和凋亡水平同步提高,以增殖层为主的细胞凋亡在糖尿病软骨的生长发育中转为主导作用.细胞外基质降解,早期软骨细胞增殖活跃,晚期增殖能力下降.褪黑素能抑制生长板软骨细胞的增殖分化.
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