Objective To investigate the growth, expansion, and metabolic characteristics of the human dermal fibroblasts cultured in a bioreactor with batch and medium exchange modes. Methods Human dermal fibroblasts separated from foreskin were seeded into a 1.5 liter CelliGen bioreactor with 5mg/ml of microcarriers. The cell growth, glucose consumption and lactate accumulation in both batch and medium exchange cultures were measured. Results The growth density of fibroblasts cultured in the bioreactor with medium-exchange mode reached 2.08×106 cell/ml, expande 29.7 folds, which was 1.81 times as high as that in batch culture. By comparison with the results obtained in T-flasks and spinners under the same medium-exchange conditions, the cell density in the bioreactor was 9.16 and 1.43 times as high as those in T-flasks and spinners respectively owing to that the limitation effect the attachment surface, nutrient exhaust, and by-product accumulation on the growth of fibroblasts in the bioreactor by using microcarriers, medium-exchange, as well as gas aeration was elimnated. Conclution The above results indicate that suspended cultures with microcarriers in bioreactors are an effective approach to rpovide large amounts of seeding cells for tissue engineering.
Objective To prepare chitosan microcarriers and to use it to cultivate rat primary hepatocytes. Methods The crosslinked chitosan microcarrier was prepared by the reaction of glutaraldehyde with chitosan. Various factors that influence the preparation were studied and the reaction conditions were optimized. Rat primary hepatocytes cultured on chitosan microcarrier were observed by using phase contrast microscope and scanning electron microscope. Results Chitosan microcarriers with good properties could be prepared by adjusting the concentration of chitosan solution and the quantity of glutaraldehyde. Rat hepatocytes cultured on chitosan microcarriers retained the spherical shape as they have in vivo. And albumin secretion can last over one week. The highest albumin secretion rate reached 26.7μg/24h/ml. Conclusion Chitosan microcarriers is a promising scaffold for hepatocyte attachment, which can be used in bioartificial liver support system.
Objective To develop an in vitro three-dimensional angiogenesis system and analyze the expression and function of CD105 in angiogenesis. Methods After primary human umbilical vein endothelial cells (HUVEC) were purified and cultured, the microcarriers were coated with HUVEC and then embedded and cultured into fibrin gel. The angiogenesis process of HUVEC on the microcarriers was formed. The expression of CD105 during this process was detected by reverse transcription polymerase chain reaction (RT-PCR). Antisense oligodeoxynucleotide (ASODN) was used to inhibit the expression of CD105 and the changes of the angiogenesis process were analyzed quantitatively. Results HUVEC on the microcarriers which were embedded into the fibrin gel, occurred the angiogenesis process of sprouts, branches and capillary networks with lumina. During this process, CD105 was over expressed in the periods of forming sprouts and branches, and depressed in the relatively steady periods including the periods before forming sprouts and after forming capillary networks. While the expression of CD105 was inhibited by ASODN, the angiogenesis process was significantly inhibited. Conclusions The expression of CD105 is varied within the angiogenesis process, over expressing during the sprouts and branches forming periods. Inhibiting the expression of CD105 could efficiently inhibit angiogenesis.