明确复方倍他米松（compound betamethasone,BT）对合并糖尿病及肩关节僵硬的退变性肩袖撕裂肌腱细胞的影响，为下一步临床用药提供参考。

采集糖尿病合并肩关节僵硬的退变性肩袖撕裂需要接受手术患者的肩袖肌腱组织完成肌腱细胞培养，于特定时间点使用细胞计数试剂盒（cell counting kit-8，CCK-8）测定细胞增殖情况，并绘制增殖曲线。采用常规培养基（对照组）、BT与含10%胎牛血清（fetal bovine serum，FBS）低糖杜贝克改良培养基（dubelcco's modified eagle medium，DMEM）按照体积比配制成带药培养基：高浓度组（V_BT:V_DMEM=1:10）、低浓度组（V_BT:V_DMEM=1:20）共3种培养基，将其分别单次作用于P₃代肌腱细胞24 h，而后在指定的时间点评估细胞形态、凋亡和活性。

P₀代糖尿病肌腱细胞增殖传代至P₃代需要6 ~ 7周，细胞形态随细胞数量的增加而逐渐变为梭形。普通光学显微镜下观察显示两组细胞用药后8 ~ 12 h细胞形态明显改变，24 h镜下观察及活力检测发现肌腱细胞大量坏死脱落，而后剩余细胞明显缩小、变圆，细胞增殖能力陷于停滞状态，高浓度组细胞形态变化更加明显；用药后7 ~ 12 d增殖能力开始逐渐恢复，细胞形态于21 d恢复至用药前状态。用药后24 h流式细胞凋亡分析显示两组凋亡率存在统计学差异，高浓度组>低浓度组，P<0.05。

合并糖尿病及肩关节僵硬的退变性肩袖撕裂肌腱细胞增殖速度缓慢，BT对此类肌腱细胞具有明显的细胞毒性，其造成的损害尽管可逆，但需要较长时间。

The treatment of degenerative rotator cuff tears combined with shoulder stiffness is extremely challenging, and there are various difficulties in postoperative rehabilitation. The application of glucocorticoid in this kind of disease is controversial while achieving obvious curative effect. However, for such patients with diabetes, the adverse effects of diabetes on tendinopathy make the clinical treatment work face greater challenges, and the use of glucocorticoid may face higher risks. However, there is a clear lack of targeted basic research at present.

To investigate the effect of compound betamethasone on degenerative rotator cuff tear tendon cells with diabetes mellitus and shoulder stiffness, so as to provide reference for further clinical use.

The rotator cuff tendon tissues of diabetic patients with shoulder stiffness and degenerative rotator cuff tear were collected for tendon culture. CCK-8 was used to detect the cell proliferation at a specific time point, and the proliferation curve was drawn. According to the volume ratio of conventional medium (control group) , compound betamethasone (BT) and low sugar DMEM medium containing 10%FBS, three kinds of media were prepared: high concentration group (V_BT:V_DMEM=1:10) and low concentration group (V_BT:V_DMEM=1:20) . The P₃ tendon cells were exposed to the three kind of medium for 24 hours, and then the cell morphology, apoptosis and activity were evaluated at the specified time point.

The proliferation and passage of P₀ generation diabetic tendon cells to P₃ generation takes 6-7 weeks, and the cell morphology gradually becomes fusiform with the increase of the number of cells. The observation under ordinary light microscope showed that the morphology of cells in the two groups changed significantly 8-12 hours after treatment, and a large number of tendon cells were found to be necrotic and exfoliated by 24-hour microscopic observation and viability detection, and then the remaining cells shrunk and became round obviously. The ability of cell proliferation was stagnated, and the morphological changes of cells in high concentration group were more obvious. The proliferation ability began to recover gradually at 7-12 days after treatment, and the cell morphology returned to the pre-treatment state at 21 days. Twenty-four hours after treatment, flow cytometry apoptosis analysis showed that there was significant difference in apoptosis rate between the two groups, high concentration group > low concentration group (P<0.05) .

The degenerative rotator cuff tear tendon cells with diabetes mellitus and shoulder stiffness proliferate slowly. Compound betamethasone has obvious cytotoxicity to this kind of tendon cells. Although the damage caused by compound betamethasone is reversible, it takes a long time.