Effect of growth hormone on proliferation and phenotype of cultured growth plate chondrocytes from pubertal rats treated with GnRHa

Objective To observe the effect of growth hormone on proliferation and phenotype of cultured growth plate chondrocytes from pubertal rats treated with GnRHa. Methods Primary chondrocytes from tibial growth plate of 5-8 female rats by trypsin-collagenase digestion were cultured in monolayer. MTT method,cell cycles detection by flow cytometry and immunohistochemical staining of PCNA and colⅡ were conducted to observe the influence of GH with different time and different concentrations on the proliferation and phenotype of chondrocytes cultured in vitro. Results GH enhanced the proliferation of chondrocytes of pubertal rats treated with GnRHa in vitro in time-dependent and concentration-dependent fashion. GH could significantly promote the proliferation of chondrocytes at day 1,day 2,day 3,day 4,day 5 and day 6,which had a significant difference compared with the control group ( P 0. 05). The optimal time for proliferation occurred at day 4. The proliferation of chondrocytes was not obvious with GH concentrations of 10 ng/ml and 20 ng/ml ( P 0. 05). The proliferative effect began to occur with GH concentration up to 50 ng/ml ( P 0. 05) and the optimal concentration was 100 ng/ml. GH also enhanced the expression of colⅡ. The optimal time for expression occurred at day 4 and the optimal concentration was 100 ng/ml. Conclusions GHenhances the proliferation and ColⅡexpression of chondrocytes from pubertal rats treated with GnRHa in vitro directly. The dose for proliferation-promotion is consistent with the dose administered in clinical practice. It provides a theoretical basis for overcoming deceleration of growth rate during GnRHa treatment.