The Study Of Basic Fibroblast Growth Factor(bFGF) On Chondrocyte Proliferation And Differentiation In Porous Tantalum-chondrocyte Composites In Vitro

Objectives To contrast the effect of basic fibroblast growth factor (bFGF) with differentconcentrations on phenotypes maintaining and dedifferentiation inhibiting of rabbitchondrocytes in porous tantalum–chondrocyte composites in vitro, and to provide theorybasis for chondral defect repair.Methods The articular chondrocytes from a immature rabbit were cultured and identifiedby type II collagen immunocytochemistry and Safranin O staining. The3rd generationchondrocytes were implanted in porous tantalum and was given bFGF with variousconcentrations. The bFGF/chondrocyte/porous tantalum composites were divided intogroup A(1ng bFGF/chondrocyte/porous tantalum), group B(10ng bFGF/chondrocyte/por-ous tantalum), group C(50ng bFGF/chondrocyte/porous tantalum), group D(chondrocy-te/porous tantalum) and group E(pure chondrocyte). The proliferation of chondrocyte wasmeasured by MTT method. The cell morphology and growth were observed by scanningelectron microscopy (SEM). Phenotypes and dedifferentiation(type I、II、IX and Xcollagen) of chondrocyte were detected by immunocytochemical method and type II,Xcollagen mRNA were tested by real-time PCR.Results1Type II collagen immunocytochemistry and Safranin O staining were positi-ve.2The result of MTT test showed that the level of chondrocyte proliferation in theexperimental group(group A, B, C, D) was higher than those of the control group(group E)(P<0.05) and more significant promotive effect when concentration of bFGF was10ng/ml.There was significant difference between groups (P<0.05).3The canning electron micr-oscope showed that chondrocyte presented better growth and attached to the surface andinner of porous tantalum, and extended to cover much of the material surface advancedstage.4The result of immunocytochemical staining showed that the expression of prote-in for collagen II and IX were strong positive in10ng/ml bFGF/tantalum/chondrocytesgroup (group B) at3th and7th day, compared with the control group(group E)(P<0.05),and there were significant difference between groups (P<0.05), while the expression ofprotein for collagen I and X were weak positive or negative(P<0.05) in10ng/ml bFGF/tan-talum/chondrocytes group (group B).5The collagen type II mRNA of chondrocytes wasup-regulated in experimental groups (group A-D), compared with the control group(groupE)(P<0.05), but collagen type X gene was down-regulated (P<0.05).Conclusions1The bFGF co-cultivated tantalum-chondrocytes could stimulateproliferation, maintain the phenotype and inhibit the hypertrophic differentiation ofchondrocytes (dedifferentiation).210ng/ml bFGF is the optimum concentration forproliferation of chondrocytes.3The bFGF co-cultivated tantalum-chondrocytes couldpromote the expression of collagen type II mRNA of chondrocytes, but inhibit collagentype X mRNA. All these data suggested that bFGF/porous tantalum/chondrocyte composites could be used in repairing cartilage defect.