Ulinastatin intervention for polymethyl methacrylate-induced MC3T3-E1 mouse preosteoblast apoptosis / 中国组织工程研究

ABSTRACT

BACKGROUND:Previous studies have indicated that ulinastatin can inhibit RANKL-induced osteoclastogenesis on RAW264.7 cells and also lower matrix metal oproteinase-9 expression and activity. However, it remains be unclear whether ulinastatin has the intervention effect on polymethyl methacrylate (PMMA)-induced MC3T3-E1 mouse preosteoblast apoptosis or not. ＜br> OBJECTIVE:To explore the intervention role of ulinastatin on the PMMA-induced MC3T3-E1 mouse preosteoblast apoptosis and its effects on type I col agen, osteocalcin, matrix metal oproteinase-2 mRNA expression. ＜br> METHODS:MC3T3-E1 mouse preosteoblasts at passages 6 and 7 were divided into four groupsblank group (only cultured MC3T3-E1 mouse preosteoblast), PMMA-induced group (MC3T3-E1 mouse preosteoblast+1 g/L PMMA bone cement suspension), low dose ulinastatin group (MC3T3-E1 mouse preosteoblast+1 g/L PMMA bone cement suspension+500 U/mL ulinastatin) and high dose ulinastatin group (MC3T3-E1 mouse preosteoblast+1 g/L PMMA bone cement suspension+5 000 U/mL ulinastatin). MTT method was adopted to detect the proliferation activity of proliferative activity of MC3T3-E1 mouse preosteoblast;alizarin red staining method was used to observe mineralization nodules of MC3T3-E1 mouse preosteoblast among different groups;the change of apoptosis rate for MC3T3-E1 cells was detected by flow cytometry analysis;semi-quantitative RT-PCR was taken to analyze type I col agen, osteocalcin, matrix metal oproteinase-2 mRNA expression level in MC3T3-E1 mouse preosteoblasts among different groups. ＜br> RESULTS AND CONCLUSION:Compared with the blank group, PMMA significantly inhibited the proliferation activity of MC3T3-E1 mouse preosteoblast (P＜0.05), and however significantly promoted cells apoptosis (P＜0.05). After addition of different concentrations of ulinastatin (500, 5 000 U/mL), the proliferation activity of MC3T3-E1 mouse preosteoblasts significantly raised (P＜0.05), and cells apoptosis rate significantly decreased (P＜0.05), showing the dose and time-dependent relation. Type I col agen and osteocalcin mRNA expression levels both significantly decreased after co-culture in PMMA group compared with the blank group (P＜0.05), matrix metal oproteinase-2 mRNA expression level, however, significantly increased (P＜0.05). After intervention with 5000 U/mL ulinastatin, type I col agen and osteocalcin mRNA expression levels both significantly increased, while matrix metal oproteinase-2 mRNA expression level significantly decreased (P＜0.05). PMMA group showed no obvious mineralization nodules. Yet, mineralization nodules were formed in the blank group, high and low dose ulinastatin groups. These results indicate that ulinastatin could have the inhibitory effect on the PMMA-induced MC3T3-E1 mouse preosteoblast apoptosis, and it could promote type I col agen and osteocalcin mRNA expression and yet suppress matrix metal oproteinase-2 mRNA expression.