Influence of ascorbic acid (AsA) concentration in culture medium on mechanical property of regenerated cartilage

The chondrocyte-agarose construct has been employed as an experimental model in the cartilage tissue engineering context. We studied the influence of L-Ascorbic acid (AsA) concentration in culture medium on mechanical property of regenerated cartilage. Cylindrical chondrocyte-agarose constructs with a diameter of 4 mm and a height of 2.5 mm were prepared as test specimens. Chondrocytes isolated from metacarpal-phalangeal joint of steers were seeded in 1 wt% agarose (type VII, Sigma) to give an initial cell density of 1 x 10 ⁷ cells/mL, and cultured in sterile culture medium (DMEM+20%FBS) within a humidified tissue culture incubator. We cultured by using levels of five AsA concentrations,0.64, 2.2, 3.2 and 6.4 pmol/10⁹ cells and without AsA. Culture medium was exchanged every two days. After culture periods of 1, 8, 15 and 22 days, tangent modulus of the cultured construct and glycos amino glycan (GAG) bio synthesis were evaluated by the unconfined compression test and the demethyl methylene blue (DMMB) assay,respectively.The structural organization of the elaborated tissue was also examined morphologically by the confocallasers cannin gmicroscope (CLSM).Result sindicated that the tangent modulus of the cultured construct The increased amount of AsA would contribute-the accelerated self-assembly of the collagen fiber network and result antimprovement in themechanical property,since the reductionability of AsA could enhance the procollagen expression in cultured chondrocytes.