210 COMPARATIVE CHARACTERIZATION OF MESENCHYMAL STEM CELLS DERIVED FROM MINIATURE PIG SYNOVIUM, SYNOVIAL FLUID AND BONE MARROW

Abstract

Mesenchymal stem cells (MSC) are a valuable cell source for cartilage tissue engineering because MSC derived from various tissues readily differentiate into skeletal cell and chondrogenic lineages. In this study, we compared the cellular characteristics of synovium (SN) and synovial fluid (SF)-derived MSC with bone marrow (BM)-derived MSC of miniature pig. Biopsies of SN and BM were collected and SF was flushed with saline solution from 6-month-old miniature pig (T-type, PWG Micro-pig, PWG Genetics Korea, South Korea). Cells were isolated from collected tissues and cultured in advanced-DMEM supplemented with 10% fetal bovine serum at 38.5°C in a humidified atmosphere of 5% CO₂ in air. The cells were then evaluated for their expression of MSC-specific markers, including CD29, CD44 and CD90 using flow cytometry. The expression of early transcriptional factors, such as Oct3/4, Nanog and Sox2 was evaluated by immunocytochemical staining and reverse transcription-PCR (RT-PCR). Multilineage differentiation of MSC were induced under conditions conductive for osteogenic, adipogenic and chondrogenic lineages and then evaluated by von Kossa and Alizarin Red S staining, Oil red O staining and Alcian Blue staining, respectively. Differentiated cells were further analysed for the expression of lineage specific markers by RT-PCR. Statistical analysis was performed using one-way ANOVA by SPSS. The SN-, SF- and BM-MSC were observed to be positive for MSC specific markers, such as CD29 (99 ± 0.2, 96 ± 0.5 and 98 ± 0.2, respectively), CD44 (97 ± 0.3, 96 ± 0.6 and 98 ± 0.5, respectively) and CD90 (95 ± 0.5, 92 ± 0.2 and 96 ± 0.3, respectively); however, haematopoietic marker CD45 (2.0 ± 2.1, 3.0 ± 1.3 and 2.0 ± 3.0, respectively) was barely detected. In all MSC, early transcription factors (Oct3/4, Nanog and Sox2) were expressed by immnocytochemical staining and the transcripts were detected by RT-PCR. Following exposure to the specific differentiation medium, all these MSC were capable of differentiating into mesenchymal lineages, such as osteogenic, adiopogenic and chondrogenic as assessed by von Kossa and Alizarin Red S staining, Oil red O staining and and Alcian Blue staining, respectively. In addition, differentiated cells from all MSC expressed the marker genes specific to osteocytes (osteonectin, Runx2), adipocytes (aP2, PRAR-γ2) and chondrocytes (aggrecan, collagen type 2) by RT-PCR. The results of this study suggested that cells isolated from miniature pig articular tissues, such as SN and SF have similar characteristics of MSCs and their differentiation ability was comparable to BM-MSC. Hence, it is possible to establish MSCs from SN and SF as alternate sources during the biopsy of synovial tissues for arthritis diagnosis. Further studies are being carried out to evaluate their in vivo differentiation potential into chondrocytes.

This study was supported by Rural Development Administration (grant No. 20110701-305-533-001-02-00) and National Research Foundation of Korea (grant No. 2011-0010252) of the Republic of Korea.