The Expression Of MGF Of Rat Osteoblasts Regulated By Mechanical Signals And The Effects Of MGF On The Physiological Behaviors Of Osteoblasts

The effects of mechanical stretching on the expression of mechano growth factor and the effects of mechano growth factor on proliferation and differentiation of osteoblasts were studied through biomechanical, cell biological and molecular biology methods. The main work and conclusions were as follows:Cyclic mechanical strain unit was improved. The improved unit can seed more cells, avoiding the trouble of gathering cells repeatedly during experiment. The assembly and disassembly of the flow chamber is very easy. The peak value and frequency could be changed according to experimental requirements. Expansion of the membrane was controlled by frequency of the electromagnetic valve and speed of the constant-flow pump.The primary Wistar rats osteoblasts were cultured from the calvaria of new-born rats by the tissue piece culture method. The osteoblasts were purified by the difference of the adhibition time with other type of cells. It was identified by the morphology, alkaline phosphatase (ALP) staining and Von Kossa staining, and the results showed that the culture osteoblasts had typical characteristics of osteoblasts. Cells from the second to sixth passages were used for the mechanical experiments.Cells were stretched using the cyclic-strain unit and static-strain unit at 15% and gathered 12h,24h,36h and 48h later, then the protein was isolated and analyzed by western blot to make sure whether the mechano growth factor(MGF) was expressed. The results showed that MGF was expressed at 12h and 24h.In order to study the effect of mechano growth factor on the proliferation and differentiation of osteoblasts, the MGF was confected solution and used to cell plate seeded cells. The proliferation was measured by MTT essay and the alkaline phosphatase (ALP) activity measured by ALP kit. The results showed that 10 ng/ml MGF increased cell proliferation and inhibited differentiation.The changes of BMP-2,cbfα-1,Col I,OCN mRNA were detected by RT-PCR. The results demonstrated that10 ng/ml MGF increased the expression of BMP-2,cbfα-1,Col I mRNA and inhibited OCN mRNA.