The Effects Of Dynamic Compressive Stress And PTHrP On The Biological Characteristics Of Rat Precartilaginous Stem Cells In Vitro

Objective Culture precartilagious stem cells planar and in calcium alginate beads, add the dynamic stress stimulation or/and thyroid hormone related peptide (PTHrP) to different groups, further revealed the proliferation and differentiation rule of PSCs and regulation mechanism.Methods The PSCs in femur epiphysis of new SD rats were isolated and purified using magnetic activated cell sorting system and cultured in vitro planar and in calcium alginate beads. Cells were randomly divided into different groups and subjected to PTHrP of different concentrations or/and compressive pressure of 90 mmHg. Cell proliferation be detected through Cell count and Cell Counting Kit-8(cck8). The specificity extracellular matrix - typeⅡCollagen of 3d cultivate cartilage cells be detected through immunohistochemical .The expression levels of typeⅡcollagen,type X collagen, aggrecan,Sox9, IGF-1, TGF-β1and PTHrP were measured by reverse transcription polymerase chain reaction(RT—PCR).Results Good state of PSCs are separated from mixture of cells throu relatively tumor-specific markers with PCNA ne fluorescence, it is displayed that cells expression FGFR - 3 which is relative specific markers and PCNA which is relatively tumor-specific markers; The cell proliferation capacity be detected though cell count and CCK - 8 method, The results show that the effective intervention group increase obviously than control group (P﹤0.05) and PTHrP intervention and stress stimulus have a synergy effect. RT - PCR tests showed that in effective intervention groups the expression of CollagenⅡ, aggrecan, Sox9 is elevatory than the control group, Collagen X expression is reduced than the control group (P﹤0.05), that the expression level of PTHrP, TGF - beta 1, IGF– 1 in 90mmg pressure stimulate group is higher than the control group (P﹤0.05) .Conclusions In vitro both PTHrP intervention and compressive stress stimulus can affect the proliferation and differentiation of PSCs;In 90mmg pressure intermittent stimulate group, the Proliferation effect is evident; The terminal differentiation of cells is delayed; Maybe it is relevant to the elevatory expression level of PTHrP; The 0.1nmol /L PTHrP have a Stimulative effect to the proliferation of PSCs and a delay effect on its terminal differentiation; Sox9 is its probable targets; the dynamic stress stimulation and thyroid hormone related peptide have a synergetic effect on promoting the proliferation and extracellular matrix secretion.