Synergic effect of combined melatonin and tofacitinib on ameliorating dextran sulfate sodium-induced colitis in rat---role of JAKs/STAT, cell-stress signaling, and inflammatory-immune reaction

BACKGROUND: This study investigated whether the combined treatment of melatonin and tofacitinib offers enhanced protection against dextran sulfate sodium-induced acute colitis (AC) in rats. Using CCD-18Co fibroblasts and a rat colitis model, we assessed the anti-inflammatory, anti-apoptotic, and immunomodulatory effects of the combination therapy. METHODS: CCD-18Co cells were grouped as A1 (CCD-18Co), A2 (CCD-18Co + lipopolysaccharide (LPS)), A3 (CCD-18Co + LPS + Melatonin), A4 (CCD-18Co + LPS + Tofacitinib), or A5 (CCD-18Co + LPS + melatonin + tofacitinib). Sprague-Dawley rats were categorized into groups 1 (normal control), 2 (AC), 3 (AC + melatonin), 4 (AC + tofacitinib), and 5 (AC + melatonin + tofacitinib), and the colons were harvested 14 days after AC induction. KEY FINDINGS: Cell viability at time points of 24, 48, and 72 h was the highest in A1, lowest in A2, and progressively increased from A3 to A5 (all P < 0.0001). The protein expression levels of inflammatory, DNA-damaged, and autophagic (ratio of LC3-BII to LC3-BI) biomarkers displayed identical patterns of apoptosis among the groups (all P < 0.0001). Additionally, the blood stool, colon leakage, and colon injury scores were the lowest in group 1, highest in group 2, and significantly progressively reduced from groups 3 to 5 (all P < 0.0001). The protein expression of the Janus kinase family-signal transducer and activator of transcriptions/cell-stress signaling, inflammation, oxidative stress, DNA-damaged, apoptotic biomarkers, and cellular expression of immune and inflammatory factors exhibited an identical pattern of colon injury scores among the groups. CONCLUSIONS: Combined melatonin-tofacitinib treatment effectively protected the colon against dextran sulfate sodium-induced damage, mainly through the suppression of Janus kinase family-signal transducer and activator of transcriptions/cell-stress signaling, inflammation, and oxidative stress.