The Effects Of Bone Morphogenetic Protein 2 In Patellar Tendon Healing

Objectives:Tendon repair is still a big challenge. In the clinical, the patellar tendon often act as autograft for the treatment of injury tendon healing. However, the patellar tendon transplant results many clinical complications and poor healing. Therefore, it is important for us to develop a effective way to promote patellar tendon healing. In this study, the tenocytes from patellar tendon were isolated and cultured. The proliferation and senescence of tenocytes were investigated. In addition, the possible benefic effects of BMP-2 in patellar tendon healing were studied.Methods and Results:1) The tenocytes of patellar tendon were isolated by transplant culture and enzyme isolation respectively. It was found that the young tenocytes isolated by transplant culture showed spindle cells, and isolated by enzyme were flat major; The old tenocytes isolated by transplant culture from the spindle-shaped to round and then flat, and old tenocytes isolated by enzyme were flat; These can provide valuable reference to our research.2) RT-PCR were used to detect the markers of isolated tenocytes. It was shown that the tenocytes from isolated by transplant culture were positive for CD44 and CD 102, the tenocytes from isolated by enzyme method were positive for CD4, CD13 and CD102. The results suggested that there were subgroups in isolated tenocytes.3) The growth curve analysis with cell number counting revealed that the cultured tenocytes were in the exponential phase in 72 hours after culture, while it was in stationary phase 124 hours after culture. So the proliferation capacity of tenocytes was limited and slow.4) The (3-galactosidase staining for tenocytes indicated that the young tenocytes isolate by transplant culture was accelerated aging follow the passage, but the old tenocytes isolate by ransplant culture was not accelerated aging follow the passage. But the tenocytes isolated by enzyme method is the opposite. The results suggested that the senescence existed in tenocytes of patellar tendon. In situ hybridization and RT-PCR were used to detect the express of BMP-2. It was shown that BMP-2 was expressed in tenocytes in patellar tendon and the isolated tenocytes. BMP-2 were use to treat the tenocytes in vitro and in vivo. The growth curve analysis, migration assay, flow cytometry and in vivo transplantion were applied to investigate the proliferation and migration of tenocytes, and the effects in patellar tendon healing. It was found that BMP-2 increase proliferation and migration of tenocytes in vitro and in vivo. Further more, in vivo transplantation of BMP-2 could promote paterllar tendon healing.Conclusions:(1) The proliferation of tenocytes was limited and the senescence existed in tenocytes from patellar tendon. (2) BMP-2 could promote tenocyte proliferation and migration, and improve damage patellar tendon healing.