The serum expression levels of IL-6, IL-8, TNF-α, C3, C4, IgA and sIgA in different groups. A, control group; B, stress group; C, UC and stress group; D, UC model alone. *P,0.05, **P<0.01. IL, interleukin; TNF, tumor necrosis factor; Ig, immunoglobulin; s, soluble; C, complement component; ns, not significant.