Abstract:
OBJECTIVE To investigate the possible mechanism of Baitouweng decoction (BTW) in the treatment of ulcerative colitis.
METHODS The UC mice were established by 3.5% dextran sodium sulfate (DSS) and randomly divided into four groups: control group, model group, BTW group and rapamycin group. The DSS administration and drug treatments were carried out simultaneously. The BTW group was given Baitouweng decoction 6.83 g·kg-1by gavage, the rapamycin group was treated with rapamycin 2 mg·kg-1 by intraperitoneal injection, and the other two groups received the same amount of 0.5% sodium carboxymethyl cellulos. Daily body weight loss and stool characteristics were recorded and the mice were sacrificed 7 days later. Colon length was measured and histopathological changes were observed. The serum inflammatory cytokines were detected by flow cytometry. The expression of mammalian target of rapamycin (mTOR), signal transducer and activator of transcription 3 (STAT3), ribosomal S6 protein kinase (P70S6K) and corresponding phosphorylated protein were detected by Western blot. The immunohistochemical detection of phosphorylated P70S6K protein expression was explored in colon tissue, and the level of cyclooxygenase-2 (COX-2) was evaluated by RT-PCR.
RESULT Compared with the control group, the body weight, the colon length, the disease activity index (DAI) and the histopathological score were decreased in colitis mice (P < 0.001). The contents of interleukin 6 (IL-6) and tumor necrosis factor-α (TNF-α) in serum, the expression of COX-2 mRNA in colon tissue, p-mTOR/mTOR, p-STAT3/STAT3 and p-P70S6K/P70S6K values were increased (P < 0.01, P < 0.001); Compared with the model group, all above clinical symptoms of mice in the BTW group and rapamycin group were improved. The contents of IL-6 and TNF-α in serum (P < 0.01, P < 0.001), the level of COX-2 mRNA in colon tissue, p-mTOR/mTOR, p-STAT3/STAT3 and p-P70S6K/P70S6K values were significantly decreased (P < 0.05, P < 0.01, P < 0.001).
CONCLUSION Baitouweng decoction can effectively prevent DSS-induced colitis in mice by inhibiting mTORC1-STAT3-COX-2 signaling pathway.