Thymosin β4 released by mast cells under stress conditions impairs intestinal epithelial barrier via IL22RA1/JAK1/STAT3 signaling in irritable bowel syndrome

Figure 4 Thymosin β4 drives intestinal permeability increase in vivo. Thymosin β4 (Tβ4) (3 mg/kg) was intraperitoneally injected into C57BL/6 mice every day for a week. A-C: Representative intestinal immunofluorescence images of (A) zonulin 1 (ZO-1) (Scale bar, 50 μm), (B) myosin light chain kinase (MLCK) and (C) IL22RA1. Scale bar, 100 μm; D: Representative FISH staining for bacterial infiltration using EUB338 probe (red) and DAPI (blue). Scale bar, 100 μm. Tβ4 (3 mg/kg) was intraperitoneally injected into Kit^W-sh/W-sh mice every day for a week; E and F: Representative intestinal immunofluorescence images of (E) ZO-1, Scale bar, 100 μm, and (F) MLCK, Scale bar, 100 μm; G: Representative FISH staining for bacterial infiltration using EUB338 probe (red) and DAPI (blue). Scale bar, 100 μm; H-J: The level of (H) diamine oxidase, (I) D-lactate and (J) bacterial endotoxin in serum. Bar, SD, ^bP < 0.01 vs the Control group. MLCK: Myosin light chain kinase; ZO-1: Zonulin 1; Tβ4: Thymosin β4.