Objective: To investigate the expressions of transforming growth factor beta 1(TGF-β1) /smad, connective tissue growth factor (CTGF), collagen I and collagen III in ankylosing spondylitis (AS).
Methods: Thirty patients with AS were included in the study. All the patients were performed with computed tomography-guided needle biopsy in sacroiiliac joint. Sera TGF-β1 and CTGF were determined by enzyme-linked immunosorbent assay (ELISA). Immunohistologic studies were performed with the alkaline phosphatase-anti-alkaline phosphatase technique to assess the expressions of TGF-β1, p-smad3, smad7, CTGF, collagen I and collagen III in sacroiiliac joint tissue samples.
Results: In the AS patients, neither serum TGF-β1 level nor serum CTGF level was found significantly different from that of the controls [(6.7±2.1)mg/L vs.(5.4±5.8)mg/L, P<0.05, (0.83±0.46)μg/L vs.(1.07±0.79 )μg/L, P<0.05]. In contrast to the healthy controls, TGF-β1 and CTGF were found upexpressed in cytoplasm of inflammatory cells in pannus and bone marrow in sacroiliac tissue samples of patients with AS [(104.5±66.2) /HP vs. (24.4±9.3) /HP, (57.94±42.40) /HP vs. (2.67±2.52) /HP]. Meantime, p-smad3 was found expressed in the nuclear, while smad7 was detected to be downexpressed. Additionally, collagen I and collagen III were found upexpressed in bone, cartilage and ligament tissue.
Conclusion: TGF-β1, CTGF, collagen I and collagen III were upexpressed in sarcoiliac joints of AS patients. TGF-β1/CTGF may play an important role in articular cartilage fibrosis and ossification of AS by smad signal pathyway.