Introduction Osteoarthritis (OA) is a common joint disease associated with articular cartilage degeneration. Cartilage damage is an irreversible process, because of the limited capacity of the adult articular chondrocytes to repair and regenerate the normal cartilage matrix architecture. To improve the therapeutic options of OA, tissue engineering based on the use of mesenchymal stem cells (MSCs) has emerged. However, the presence of inflammatory cytokines, such as interleukin-1β (IL-1β) during chondrogenesis reduces the efficacy of cartilage engineering repair procedures, by preventing chondrogenic differentiation. Previous studies have shown that pulsed electromagnetic fields (PEMFs) stimulate anabolic processes in OA cartilage and limit IL-1β catabolic effects. We investigated the role of PEMFs during chondrogenic differentiation of MSCs, isolated from bovine synovial fluid, in the absence and in the presence of IL-1β. Materials and Methods Pellets of MSCs were differentiated for 3 and 5 weeks with transforming growth factor-β3 (TGF-β3), in the absence and in the presence of IL-1β and exposed or unexposed to PEMFs. Proteoglycans (PGs) synthesis and PG content were measured by radioactive 35S-sulphate incorporation and dimethylmethylene blue assay, respectively. Real-time RT-PCR was performed to analyze type II collagen and aggrecan expression. Histological analysis for haematoxylin and eosin and for alcian blue and immunohistochemistry for type II collagen and aggrecan were carried out on pellet sections. For statistical analysis, comparisons between groups were performed using Student’s T test and p<0.05 level was considered significant. Results Biochemical, quantitative real-time RT-PCR and histological results showed that PEMFs alone or in the presence of TGF-β3, play a limited role in promoting chondrogenic differentiation. Notably, in the presence of IL-1β and TGF-β3 a recovery on PG synthesis, PG content, aggrecan and type II collagen mRNA expression in the PEMF-exposed compared to unexposed pellets was observed. Also, in the same experimental conditions, histological and immunoistochemical results showed an increase in staining for alcian blue, type II collagen and aggrecan in PEMF exposed pellets. Discussion The presence of inflammatory cytokines, such as IL-1β in human joints, due to arthritis or trauma, may explain why existing cartilage engineering repair strategies that rely on the in situ differentiation of MSCs, fail to provide a reliably successful. Our results support the hypothesis that PEMF treatment may favor chondrogenic differentiation in inflammatory conditions. Conclusions This study shows a significant role of PEMFs in counteracting the IL-1β induced inhibition on chondrogenesis, suggesting a possible therapy for improving the clinical outcome of cartilage repair procedures.
Electromagnetic fields counteract IL-1beta activity during chondrogenesis of bovine mesenchymal stem cells
ONGARO, Alessia;PELLATI, Agnese;DE MATTEI, Monica
2013
Abstract
Introduction Osteoarthritis (OA) is a common joint disease associated with articular cartilage degeneration. Cartilage damage is an irreversible process, because of the limited capacity of the adult articular chondrocytes to repair and regenerate the normal cartilage matrix architecture. To improve the therapeutic options of OA, tissue engineering based on the use of mesenchymal stem cells (MSCs) has emerged. However, the presence of inflammatory cytokines, such as interleukin-1β (IL-1β) during chondrogenesis reduces the efficacy of cartilage engineering repair procedures, by preventing chondrogenic differentiation. Previous studies have shown that pulsed electromagnetic fields (PEMFs) stimulate anabolic processes in OA cartilage and limit IL-1β catabolic effects. We investigated the role of PEMFs during chondrogenic differentiation of MSCs, isolated from bovine synovial fluid, in the absence and in the presence of IL-1β. Materials and Methods Pellets of MSCs were differentiated for 3 and 5 weeks with transforming growth factor-β3 (TGF-β3), in the absence and in the presence of IL-1β and exposed or unexposed to PEMFs. Proteoglycans (PGs) synthesis and PG content were measured by radioactive 35S-sulphate incorporation and dimethylmethylene blue assay, respectively. Real-time RT-PCR was performed to analyze type II collagen and aggrecan expression. Histological analysis for haematoxylin and eosin and for alcian blue and immunohistochemistry for type II collagen and aggrecan were carried out on pellet sections. For statistical analysis, comparisons between groups were performed using Student’s T test and p<0.05 level was considered significant. Results Biochemical, quantitative real-time RT-PCR and histological results showed that PEMFs alone or in the presence of TGF-β3, play a limited role in promoting chondrogenic differentiation. Notably, in the presence of IL-1β and TGF-β3 a recovery on PG synthesis, PG content, aggrecan and type II collagen mRNA expression in the PEMF-exposed compared to unexposed pellets was observed. Also, in the same experimental conditions, histological and immunoistochemical results showed an increase in staining for alcian blue, type II collagen and aggrecan in PEMF exposed pellets. Discussion The presence of inflammatory cytokines, such as IL-1β in human joints, due to arthritis or trauma, may explain why existing cartilage engineering repair strategies that rely on the in situ differentiation of MSCs, fail to provide a reliably successful. Our results support the hypothesis that PEMF treatment may favor chondrogenic differentiation in inflammatory conditions. Conclusions This study shows a significant role of PEMFs in counteracting the IL-1β induced inhibition on chondrogenesis, suggesting a possible therapy for improving the clinical outcome of cartilage repair procedures.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
