血管内皮生长因子在新生鼠胫骨生长板软骨细胞中的表达

Expression of vascular endothelial growth factor and its receptors Flt-1 and KDR/Flk-1 in tibial growth plate chondrocytes of neonatal rat

目的:探讨血管内皮生长因子(VEGF)在鼠生长板软骨细胞增殖、分化和矿化过程中的自分泌作用。方法:新生鼠(1～2d)10只,切取干骺部软骨组织,采用免疫组织化学方法(5只)和RT-PCR方法(5只),检测VEGF及其受体Flt-1和KDR/Flk-1在胫骨生长板中的表达。结果:免疫组织化学染色VEGF、Flt-1和KDR/Flk-1在生长板的上肥大区、下肥大区和矿化区中的软骨细胞表达强阳性,在增殖区少数软骨细胞中呈阳性表达,在静止区软骨细胞中表达阴性。RT-PCR检测的5只鼠中除1只不表达Flt-1外,VEGF(251 bp)、Flt-1(272 bp)和KDR/Flk-1(252 bp)在软骨组织中均清晰表达。结论:VEGF及受体Flt-1和KDR/Flk-1在生长板软骨中的表达具有高度一致性,并且随着软骨细胞的分化成熟表达逐渐增强。提示VEGF在生长板软骨细胞的增殖、分化和矿化过程中,可以自分泌作用方式起重要调节作用。

Objective： To study the autocrine function of vascular endothelial growth factor （VEGF） and its receptors Fit-1 and KDR/Flk-1 in the proliferation, differentiation, and mineralization of growth plate chondrocytes of neonatal rat. Methods： Growth plate cartilages were sampled from 10 neonatal rats of day 1 to day 2, and the expressions of VEGF and its receptors Flt-1 and KDR/Flk-1 were examined by staining and reverse transcriptase polymerase chain reaction. Results： The expressions of VEGF and its receptors Flt-1 and KDR/Flk-1 were strongly positive in the upper and lower hypertrophic zones and mineralized zone of tibial growth plate cartilage and negative in the resting zone. Of the 5 neonatal rats detected by RT-PCR, the mRNAs of VEGF （251 bp）, Flt-1 （272 bp）, and KDR/Flk-1 （252 bp） were clearly detected in the fibial growth plate cartilage of 4 neonatal rats, and 1 neonatal rat did not express Flt-1 mRNA. Conclusion： The expression pattern of VEGF and its receptors Flt-1 and KDR/Flk-1 is almost identical in the growth plate cartilage of neonatal rat, and their expressions increased with the process of chondrocyte differentiation and maturation. VEGF might play an important autocrine role in the proliferation, differentiation, and mineralization of growth plate chondrocytes.