Bone morphogenetic protein 2 stimulated osteo-chondrogenic differentiation of patellar tendon-derived stem cells isolated from a failed tendon-healing animal model of tendinopathy / 中国组织工程研究

ABSTRACT

BACKGROUND:The pathogenesis of tendinopathy remains unclear and hence treatment of tendinopathy is usualy paliative. OBJECTIVE:To investigate the effects of bone morphogenetic protein 2 on the osteogenic and chondrogenic differentiation of patelar tendon-derived stem cels isolated from colagenase-induced tendinopathy ratsin vitro. METHODS: Patelar tendon-derived stem cels were isolated from patelar tendons of colagenase-induced tendinopathy rats. The multi-differentiation potential of patelar tendon-derived stem cels at passage 3 was identified by osteogenic, adipogenic and chondrogenic differentiation assays. The patelar tendon-derived stem cels were cultured to the 3rd passage in complete culture medium, and then the cels were divided into two groups with (experimental group) or without recombinant human bone morphogenetic protein 2 (control group) until the cels reached confluence for 7 days. Their osteogenic response to bone morphogenetic protein 2in vitro was examined by alizarin red S staining of calciumnodule formation and quantification assay. The patelar tendon-derived stem cellpelets were cultured in complete culture medium with (experimental group) or without bone morphogenetic protein 2 (control grup) for 21 days. Chondrogenic differentiation of the cellpelets was evaluated by hematoxylin-eosin staining, alcian blue staining, immunohistochemical staining for Sox9 and colagen type II. RESULTS AND CONCLUSION:Primary patelar tendon-derived stem cels from the tendinopathy rats culturedin vitro showed clonal growth; after passage, spindle fibroblast-like and flat-like cels were detectable. The cels were positive for oil red O staining at 10 days after adipogenic induction, positive for alizarin red staining at 7 days after osteogenic induction, and positive for hematoxylin-eosin staining and immunohistochemical staining of colagen type II at 14 days after chondrogenic induction. After patelar tendon-derived stem cels were induced with recombinant human bone morphogenetic protein 2 for 7 days, the result of alizarin red staining was positive in the experimental group, but negative in the control group without recombinant human bone morphogenetic protein 2. The difference in the result of alizarin red staining between the two groups was statisticaly significant. After patelar tendon-derived stem cels were induced with recombinant human bone morphogenetic protein 2 for 21 days, the results of hematoxylin-eosin staining, alcian blue staining, immunohistochemical staining for Sox9 and colagen type II were al positive. In conclusion, bone morphogenetic protein 2 could stimulate the osteogenic and chondrogenic differentiation of patelar tendon-derived stem cels isolated from colagenase-induced tendinopathy rats in vitro, which can help to better understand the pathogenesis of tendinopathy.