Repair of osteochondral defects using human transforming growth factor beta 1 gene transfected bone marrow stem cells combined with calcium alginate

Sun Jun1, Hou Xiao-kui2, Li Xu2, Zhang Ru-ming1

1Department of Orthopaedics, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200021, China; 2Department of Orthopaedics, Ninth People’s Hospital of Shanghai Jiao Tong University, Shanghai 200021, China

Sun Jun☆, Doctor, Attending physician, Department of Orthopaedics, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200021, China
drsunjun@163.com

Received:2007-10-29
Accepted:2008-05-26

Abstract
AIM: To transduce the human transforming growth factor-β1 (hTGF-β1) gene to the bone marrow stem cells (BMSCs) and then combine with the degradable alginate to compose the tissue engineering artificial cartilage with biological activity, expecting to get a better integration of the cartilages.
METHODS: Eighteen masculine goats of 12 months old were provided by the animal experiment center of the Ninth Hospital Affiliated to Shanghai Jiao Tong University. The recombinant adenoviruses carrying hTGF-β1 were provided by the Orthopaedic Laboratory of the Ninth Hospital Affiliated to Shanghai Jiao Tong University. Calcium chloride and sodium alginate were the products of Gibco Company. Eight milliliters of bone marrow were obtained from the iliac crest of the goats. The adherent method was used to separate and culture the BMSCs. The third passage cells were transduced with hTGF-β1 and incubated overnight. An acute osteochondral defect model was created in the weight-bearing area of the medial femoral condyle on the both knees of eighteen goats. The goats were randomized into three groups, with six in each group. In the group of transduced cells with calcium alginate, the hTGF-β1 gene transduced BMSCs were suspended in the 1.2% sodium alginate. The cell density was adjusted to 5×1010 cells L-1. Five milliliters of the suspension were injected into the osteochondral defects, and excessive 2.5% calcium chloride was dropped to make the calcium chloride and sodium alginate cross-link to form calcium alginate gels. In the compound control group, the same method was used to inject the gels of non-gene transduced BMSCs into the calcium alginate gels. In the model group, none of the intervention was given. Western blot was employed to detect the expression of the exogenous gene. The reparative tissues were determined for the morphology observation and the defect scoring.
RESULTS: After the transduction of the hTGF-β1 gene, the BMSCs expressed hTGF-β1, synthesized the extracellular matrix of type II collagen and excreted aggrecan. At 24 weeks after the transplantation, the group of transduced cells with calcium alginate got a hyaline cartilage-like restoration. The compound control group and the model group got a fibrous tissue or fibrocartilage-like repair. Comparing the reparative tissues of 12 weeks and 24 weeks, the scores of the group of transduced cells with calcium alginate and the compound control group were significantly higher than those in the model group (P < 0.05). The scores of the reparative tissue in the group of transduced cells with calcium alginate were significantly higher than those in the compound control group (P < 0.05). The scores in the group of transduced cells were significantly increased as the prolonging duration (P < 0.05).
CONCLUSION: The experiments combine the tissue engineering and molecular biology with a success. The gene-transduced BMSCs can make the hTGF-β1 bring into effect continuously and effectively, and gradually transform into mature chondrocytes to excrete the matrix. The hTGF-β1 gene transduced BMSCs combined with calcium alginate could repair the osteochondral defects with satisfactory results.

Sun J, Hou XK, Li X, Zhang RM.Repair of osteochondral defects using human transforming growth factor beta 1 gene transfected bone marrow stem cells combined with calcium alginate.Zhongguo Zuzhi Gongcheng Yanjiu yu Linchuang Kangfu 2008;12(29):5636-5638 [www.zglckf.com/zglckf/ejournal/upfiles/08-29/29k-5636 (ps).pdf]