Durgam Sushmitha S, Altmann Nadine N, Coughlin Haley E, Rollins Audrey, Hostnik Laura D
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, 601 Vernon L. Tharp Street, Columbus, OH, 43210, USA.
Stem Cells Int. 2019 Dec 27;2019:1602751. doi: 10.1155/2019/1602751. eCollection 2019.
There is increased incidence of tendon disorders and decreased tendon healing capacity in people with diabetes mellitus (DM). Recent studies have also suggested pathological ossification in repair tendon of people with DM. Therefore, the objective of this study is to investigate the effects of insulin supplementation, an important pathophysiologic stimulus of DM, on tendon progenitor cell (TPC) proliferation and in vitro osteogenic capacity. Passage 3 TPCs were isolated from collagenase-digested, equine superficial digital flexor tendons. TPC proliferation was measured via MTT assay after 3 days of monolayer culture in medium supplemented with 0, 0.007, 0.07, and 0.7 nM insulin. In vitro osteogenic capacity of TPCs (Alizarin Red staining, osteogenic mRNA expression, and alkaline phosphatase bioactivity) was assessed with 0, 0.07, and 0.7 nM insulin-supplemented osteogenic induction medium. Insulin (0.7 nM) significantly increased TPC proliferation after 3 days of monolayer culture. Alizarin Red staining of insulin-treated TPC osteogenic cultures demonstrated robust cell aggregation and mineralized matrix secretion, in a dose-dependent manner. Runx2, alkaline phosphatase, and Osteonectin mRNA and alkaline phosphatase bioactivity of insulin-treated TPC cultures were significantly higher at day 14 of osteogenesis compared to untreated controls. Addition of picropodophyllin (PPP), a selective IGF-I receptor inhibitor, mitigated the increased osteogenic capacity of TPCs, indicating that IGF-I signaling plays an important role. Our findings indicate that hyperinsulinemia may alter TPC phenotype and subsequently impact the quality of repair tendon tissue.
糖尿病患者肌腱疾病的发病率增加，且肌腱愈合能力下降。最近的研究还表明，糖尿病患者修复中的肌腱会发生病理性骨化。因此，本研究的目的是探讨补充胰岛素（糖尿病的一种重要病理生理刺激因素）对肌腱祖细胞（TPC）增殖和体外成骨能力的影响。从经胶原酶消化的马浅屈肌腱中分离出第3代TPC。在补充了0、0.007、0.07和0.7 nM胰岛素的培养基中进行单层培养3天后，通过MTT法测定TPC增殖。使用补充了0、0.07和0.7 nM胰岛素的成骨诱导培养基评估TPC的体外成骨能力（茜素红染色、成骨mRNA表达和碱性磷酸酶生物活性）。单层培养3天后，胰岛素（0.7 nM）显著增加了TPC增殖。胰岛素处理的TPC成骨培养物的茜素红染色显示，细胞聚集和矿化基质分泌呈剂量依赖性增强。与未处理的对照组相比，胰岛素处理的TPC培养物在成骨第14天时，Runx2、碱性磷酸酶和骨连接蛋白mRNA以及碱性磷酸酶生物活性显著更高。添加选择性IGF-I受体抑制剂鬼臼苦素（PPP）可减轻TPC成骨能力的增加，表明IGF-I信号传导起重要作用。我们的研究结果表明，高胰岛素血症可能会改变TPC表型，进而影响修复肌腱组织的质量。
