持续激活β-连环蛋白对小鼠成骨细胞增殖和凋亡的影响

Effect of continuous activation of β-catenin on proliferation and apoptosis of osteoblasts in mice

目的观察持续激活β-连环蛋白(β-catenin)对小鼠成骨细胞增殖和凋亡的影响。方法新生3 d基因型为3.2 kb-Cre;β-catentin exon 3 FX+/+小鼠及野生型(WT)小鼠各20只分别作为CA-β-catenin组和对照组,2组均腹腔注射他莫昔芬(TM)以持续激活β-catenin(CA-β-catenin)。持续激活1个月后分离培养小鼠原代成骨细胞,并进行形态观察,收集胫骨标本行增殖(Brdu)染色,TUNEL凋亡染色,细胞周期相关因子(c-myc、cyclin Y)的免疫组化实验。结果与对照组小鼠相比,CA-β-catenin组小鼠成骨细胞增殖增多,凋亡减少,差异有极显著性统计学意义(P<0.01);CA-β-catenin组G1期关键调节因子c-myc、G2期调节因子cyclin Y表达高于对照组,差异有统计学意义(P<0.05)。结论持续激活β-catenin可使小鼠成骨细胞增殖增多、凋亡减少,一直处于高增殖状态。

Objective To observe the effect of continuous activation ofβ-catenin on proliferation and apoptosis of mouse osteoblasts.Methods The genotype at 3 days after birth was 3.2 kb-Cre.Twenty of theβ-catentin exon 3 FX+/+gene mice and 20 of the wild-type mice in the same litter were treated as CA-β-catenin group and control group,respectively.The mice in both two groups received intraperitoneal injection of tamoxifen(TM)to continuously activate CA-β-catenin.After 1 month of continuous activation,primary osteoblasts of mice were isolated and cultured,and the morphology was observed.Tibial specimens were collected for proliferation(Brdu)staining,TUNEL apoptosis staining,and immunohistochemical staining of cell cycle related factors(c-myc and cyclin Y).Results Compared with control group,the proliferation of osteoblasts was increased and the apoptosis of osteoblasts was decreased in the CA-β-catenin group,the differences were statistically significant(P<0.01).The expressions of key regulatory factors c-myc in G1 phase and cyclin Y in G2 phase were higher in the CA-β-catenin group than those in the control group,the differences were statistically significant(P<0.05).Conclusion Continuous activation ofβ-catenin can increase the proliferation and decrease the apoptosis of mouse osteoblasts and keep them in a state of high proliferation.