背景：近年研究发现，激素性股骨头坏死模型中存在大量凋亡骨细胞，而 Caspase-3及 Bcl-2为调节细胞凋亡的两个重要因子。目的：观察 Bcl-2和 Caspase-3在激素性股骨头坏死大鼠模型中的表达及二者的相关性。方法：选取健康 Wistar 大鼠60只随机分为2组，实验组臀肌注射泼尼松龙12.5 mg/kg，每周2次，制备激素性股骨头坏死模型；对照组注射等量生理盐水。分别于给药后4，8，12周获取离体大鼠股骨头，采用苏木精-伊红染色观察骨组织形态学改变，免疫组织化学染色观察 Bcl-2和 Caspase-3蛋白的表达水平，并采用直线相关分析 Bcl-2和 Caspase-3的相关性。结果与结论：对照组及实验组股骨头外形均完整，软骨面平整、光滑。随着给药时间的延长，实验组大鼠股骨头内骨小梁逐渐变细，脂肪细胞增多，骨陷窝空虚率明显升高。免疫组织化学染色显示：与对照组比较，实验组大鼠股骨头 Caspase-3表达明显增高(P <0.01)，且随给药时间的延长呈逐渐增高趋势；而 Bcl-2的表达显著低于对照组(P <0.01)。相关分析结果显示 Bcl-2和 Caspase-3在各组内的表达不具有相关性。提示激素可提高 Caspase-3的表达促进骨细胞凋亡，降低 Bcl-2的表达抑制抗凋亡作用，进而导致激素性股骨头坏死的发生和发展。%BACKGROUND: Recent studies have shown that a large amount of apoptotic osteocytes in the model of steroid-induced necrosis of the femoral head. Caspase-3 and Bcl-2 are two important factors for regulation of cel apoptosis. OBJECTIVE: To observe Bcl-2 and Caspase-3 levels in a rat model of femoral head necrosis and their correlation. METHODS: Sixty healthy Wistar rats were randomly divided into two groups (n=30). Experimental group was treated with gluteal muscle injection of prednisolone 12.5 mg/kg, twice per week, for establishing a femoral head necrosis model; control group was injected with the same amount of normal saline. Rat femoral head was removed after 4, 8 and 12 weeks respectively. Bone tissue morphological changes were observed by hematoxylin-eosin staining and the protein expression levels of Bcl-2 and Caspase-3 were observed using immunohistochemical staining. Linear correlation analysis was performed for analysis of correlation between Bcl-2 and Caspase-3. RESULTS AND CONCLUSION: Femoral heads were complete in the experimental and control groups with smooth and flat cartilage surface. In the experimental group, the trabecular bone in the femoral head gradual y became thinner, the number of adipose cells increased and percentage of empty lacunae significantly increased with the time of administration. Caspase-3 expression increased significantly in the experimental group compared with the control group (P < 0.01), trending to gradual y increase with the time of administration. Conversely, the expression of Bcl-2 was lower in the experimental group than the control group (P < 0.01). The linear correlation analysis showed that there was no correlation between Bcl-2 and Caspase-3. These findings indicate that steroids can increase the expression of Caspase-3 promoting apoptosis of osteocytes and reduce the expression of Bcl-2 inhibiting anti-apoptotic role, which leads to the occurrence and development of steroid-induced necrosis of the femoral head.
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