Chitosan-based gels as bioactive carriers for bone marrow mesenchymal stem cells:A cytocompatibility study

Zhong LI; Liu YANG; Gang DAI; Fuyou WANG; Xuhong JIN; Xiaojun DUAN

ABSTRACT

BACKGROUND:

Chitosan-disodium β-glycerol phosphate (C/GP) gel has been shown to be compatible with the entrapment of viable chondrocytes, and bone marrow mesenchymal stem cells (BMSCs) are considered to be the potential cells used in tissue engineering. This experiment is aimed to observe the cytocompatibility of BMSCs with C/GP gel.

OBJECTIVE:

To study the effect of C/GP gel on the growth, proliferation and chondrogenic differentiation in vitro cultured BMSCs and explore a new carrier for the application of cartilage tissue engineering.

DESIGN:

Completely randomized controlled experiment.

SETTING:

Department of Bone and Joint Surgery, Affiliated Hospital of Luzhou Medical College; Center Laboratory of Southwest Hospital Affiliated to the Third Military Medical University of Chinese PLA.MATERIALS The experiment was performed in Center Laboratory of Southwest Hospital Affiliated to the Third Military Medical University of Chinese PLA between October 2005 and April 2006, Six adult female mini-pigss were employed. C/GP gel is prepared by mixture the HCI solution of chitosan with salt solution of β-glycerol phosphate, allowed gel at 37 ℃ in incubator for about 5 to 10 minutes.

METHODS:

① BMSCs culture 4-6 mL of bone marrow harvested from the posterior superior lilac crest were plated at 20 ×10<'6>/100 mm dish and then grown for 14 days in complete media, consisting of DMEM/F-12 supplemented with 10% fetal ovine serum. Cells were harvested and re-seeded for subculture. ② BMSCs differentiation assays Osteogenic differentiation was assessed by histologic detection of alkaline phosphatase activity and calcium in cultures under osteogenic conditions. Chondrogenic differentiation was evaluated by histology for toluidine blue and immunohistochemistry for type Ⅱ collagen in cultures under chondrogenic conditions. ③ In vitro assays, expanded BMSCs were suspended in C/GP solution and allowed gel at 37 ℃ in incubator for about 5 to 10 minutes, then cultured under chondrogenic conditions for 3 weeks. Cells attached to and viability in C/GP gel was monitored with the aid of an inverted light microscope. Chondrogenic differentiation of cell in C/GP gel were assessed by histological and immunohistocbemistry. The cell proliferated was monitored by MTT after 2, 5, 8 days seeding.MAIN OUTCOME

MEASURES:

① Characterization of mini-pigs' BMSCs; ② BMSCs attached to and viability in C/GP gel; ③ Chondrogenic differentiation of BMSCs in C/GP gel; ④ BMSCs proliferated in C/GP gel.

RESULTS:

① Characterization of mini-pigs' BMSCs Cultured BMSCs showed fibroblastic morphology and were able to differentiate to chondrocytes or osteogenic cells under chondrgenic or osteogenic cultured condition respectively. ②BMSCs attached to and viability in C/GP gel BMSCs attached to and remained > 90% viable in C/GP gels immediately post-casting, and throughout the 21 days, using MTT staining. ③ Chondrogenic differentiation of BMSCs in C/GP gel During 21 days culture period in vitro, chondrogenic induced BMSCs produced amounts of de novo cartilage matrix in the chitosan, as assessed by histological and biochemical criteria. ④ BMSCs proliferated in C/GP gel Chondrogenic induced BMSCs cultured in C/GP gels continued to proliferate. There was a significant difference among the values of optical density in the cells-gel constructs compared to the controls without cells after 2, 5, and 8 days of culture (P<0.05).

CONCLUSION:

It is confirmed that C/GP gel shows good cytocompatibility with BMSCs and contributes to the growth, proliferation and chondrogenic differentiation for BMSCs in vitro culture. C/GP gel can be a potential cell-carrier for tissue engineering of articular cartilage.