Melton Joel Thomas Kirk, Clarke Nicholas M P, Roach Helmtrud I
J Bone Joint Surg Am. 2006 Nov;88 Suppl 3:155-61. doi: 10.2106/JBJS.F.00542.
An investigation of matrix metalloproteinase-9 (MMP-9) and its influence on vascular invasion in the secondary ossification center at the chondroepiphysis of developing long bones was undertaken. The effect of MMP-9 was compared with that of basic fibroblast growth factor (b-FGF), a potent angiogenic factor, and we assessed the chorioallantoic membrane (CAM) culture as a model for angiogenesis in osteochondral tissue.
Seventy-two femoral and seventy-two humeral heads of thirty-six four-day postnatal rabbits were dissected immediately after each animal was killed. Solutions of MMP-9, b-FGF, and phosphate-buffered saline solution were applied, and the femoral and humeral chondroepiphyseal explants were incubated for ten days in CAM culture. This was used as an in vivo model to investigate the growth of blood vessels into the femoral and humeral heads of the neonatal rabbit. The explants were harvested from the CAM culture and analyzed histologically. A three-day incubation was also performed to look for early signs of vascular ingrowth into the cartilage matrix.
One hundred and twenty epiphyses from thirty rabbits were placed onto CAM culture successfully; of these, two were harvested at three days to assess early changes and 118 were harvested at ten days. Forty of the 118 cultures were still viable when harvested after ten days, giving a 33% yield. Both MMP-9 and b-FGF caused an increased vascular invasion into the chondroepiphysis. New blood vessels derived from the chorioallantoic membrane within cartilage canals were more numerous in MMP-9 treated epiphyses, and larger canals were more commonly seen when compared with a control group.
These findings confirmed that b-FGF is angiogenic at the chondroepiphysis. Matrix metalloproteinase-9 appears to be implicated in vascular invasion and induces the formation of new cartilage canals at the chondroepiphysis. The CAM culture model was a useful model for investigating angiogenesis in osteochondral tissue.
This study adds to the understanding of the complex biochemical interaction that occurs in cartilage when the advancing vasculature begins growing into the chondroepiphysis. A better knowledge of this angiogenic process will enable a better understanding of the pathological failure or disturbance of vasculogenesis, which results in dysplastic growth disorders and osteonecrosis.
对基质金属蛋白酶-9（MMP-9）及其对发育中长骨软骨骨骺次级骨化中心血管侵袭的影响进行了研究。将MMP-9的作用与强效血管生成因子碱性成纤维细胞生长因子（b-FGF）的作用进行了比较，并评估了绒毛尿囊膜（CAM）培养作为骨软骨组织血管生成模型的效果。
在处死36只出生后4天的兔子后，立即解剖其72个股骨头和72个肱骨头。应用MMP-9、b-FGF溶液和磷酸盐缓冲盐溶液，并将股骨和肱骨软骨骨骺外植体在CAM培养中孵育10天。这被用作体内模型来研究血管向新生兔股骨头和肱骨头的生长情况。将外植体从CAM培养中取出并进行组织学分析。还进行了为期3天的孵育以寻找血管长入软骨基质的早期迹象。
30只兔子的120个骨骺成功置于CAM培养中；其中，2个在3天时取出以评估早期变化，118个在10天时取出。118个培养物中有40个在10天后取出时仍存活，存活率为33%。MMP-9和b-FGF均导致血管向软骨骨骺的侵袭增加。与对照组相比，MMP-9处理的骨骺中软骨管内源自绒毛尿囊膜的新血管更多，且更常出现较大的管道。
这些发现证实b-FGF在软骨骨骺处具有血管生成作用。基质金属蛋白酶-9似乎与血管侵袭有关，并诱导软骨骨骺处新软骨管的形成。CAM培养模型是研究骨软骨组织血管生成的有用模型。
本研究增加了对血管系统开始长入软骨骨骺时软骨中发生的复杂生化相互作用的理解。对这一血管生成过程的更好了解将有助于更好地理解血管生成的病理失败或紊乱，其会导致发育异常性生长障碍和骨坏死。
