Serum-free culture of rabbit meniscal fibrochondrocytes: Proliferative response

We have formulated a serum‐free medium capable of supporting DNA synthesis in rabbit meniscal fibrochondrocytes at a level equivalent to 10% fetal bovine serum (FBS). The medium consists of a 1:1 mixture of Dulbecco's Modified Eagle's Medium and Ham's F‐12 medium supplemented with transferrin (1 μg/ml), selenium (1 pg/ml), trace metal mix (1:100), dexamethasone (100 ng/ml), insulin‐like growth factors I and II (50 ng/ml each), pituitary fibroblast growth factor (100 ng/ml), and lactalbumin hydrolysate (2 μg/ml). Endothelial cell growth supplement could be substituted for lactalbumin hydrolysate to obtain similar results. Ventrex PC‐1, a commercially available, low‐protein, serum‐free medium, was found to support proliferation of fibrochondrocytes but not as well as 10% FBS or our medium formulation. Lipid supplements, which are known to support the serum‐free growth of hyaline chondrocytes, were found to be either of no value or antagonistic for the culture of fibrochondrocytes. Likewise, vitamin E alone, progesterone, putrescine, and hydrocortisone were also without benefit in our culture system. Thecells had a more chondrocytic morphology when grown in defined medium as opposed to 10% FBS. The results of this study should now make it possible to identify and quantitate those factors necessary to affect meniscal repair by utilizing further techniques in vitro.