Background/Purpose: Uncontrolled collagen synthesis and deposition occur in various diseases such as hepatic fibrosis, scleroderma.Tofacitinib is a selective JAK-kinase (1/3)inhibitor.Currently it is used in the treatment of rheumatoid arthritis.The aim of the study is to investigate the effect of JAK-STAT signal pathway inhibition on collagen biosynthesis in fibroblast cell-culture.Methods: BJ-CRL1474^®(skin) and BRL3A^®(hepatic) fibroblast cell cultures were proliferated in the appropriate medium.Tofacitinib was administered to fibroblast cells proliferating on 96-well flasks at concentrations of 25nM,50nM,100nM,200nM,400Nm and 800nM, respectively.Cell viability and quantity were read by spectrophotometer.Tissue metalloproteinase inhibitor(TIMP-1),matrixmetalloproteinase-3(MMP-3), transforming growth factor (TGF-1β) and hydroxyproline levels were measured by ELISA method.Results: The cytotoxic effect of tofacitinib started at 100 nM concentration(p<0.05). The highest effect was obtained at 800nM.The cytotoxic effect at concentrations of 400nM and 800nM was higher than at 100nM and 200nM concentrations(p<0.05)(Figure1).The time-dependent cytotoxic effect of tofacitinib was significantly higher at 72th hours than at 24th and 48th hours at all concentrations(p<0.05)(Figure1).TFG-1β,the major stimulus of collagen synthesis, was found to be significantly low even at 25 nM concentration(p<0.05).The lowest concentration was reached at 800nM(p<0.05).There was a significant decrease in MMP-3, TIMP-1 and hydroxyproline levels respectively(p<0.05).The decline in all three biomarkers started at a concentration of 100nM.The maximum decrease in the levels of four biomarkers was observed at a concentration of 800nM(Figure).The results in both cell cultures were similar and not statistically significant(p>0.05).Conclusion:Tofacitinib was shown to reduce fibroblast proliferation and viability in fibroblast cell culture.The decrease in the levels of TGF-β, which is also the main stimulus of collagen synthesis and is also released from fibroblasts, may be due to reduced release of TGF-β.The level of hydroxyproline in the collagen structure is expected to decrease.We found that the level of MMP-3 was also reduced.MMP-3 was not needed in conditions such as collagen synthesis decreased and in vitro.We found a decrease in TIMP-1, an inhibitor of MMP-3. JAK kinase inhibitor, tofacitinib inhibited fibroblast cell proliferation in fibroblast cell culture by time and concentration.

Table-1: Effect of Tofacitinib on  levels of TGF-1β, MMP-3,TIMP-1 and hydroxyproline.

 *p<0.05, **p<0.05 , #p<0.005