Tofacitinib protects intestinal epithelial cells against oxygen-glucose deprivation/reoxygenation injury by inhibiting the JAK/STAT3 signaling pathway

The present study aimed to investigate the role and potential mechanism of action of tofacitinib (Tofa) in intestinal ischemia/reperfusion (I/R) injury. The normal rat small intestine epithelial cell line, IEC-6, was used to establish an I/R injury model by inducing oxygen-glucose deprivation/reoxygenation (OGD/R). Cells were divided into the following five groups: Control, OGD/R, OGD/R with 50, 100 and 200 nM Tofa. Following Tofa administration, cell viability was measured using Cell Counting Kit-8 assay and a lactate dehydrogenase detection kit. The expression levels of cell apoptosis-related proteins, Bcl-2, cleaved-caspase-3 and cleaved-caspase-9 were detected using western blot analysis. Additionally, the levels of oxidative stress-related markers, such as reactive oxygen species (ROS), malondialdehyde (MDA) and superoxide dismutase (SOD), and inflammatory cytokines, TNF-α, IL-6 and IL-1β were assessed using the colorimetric method. Western blot analysis was also used to measure the expression levels of the Janus kinase (JAK)/STAT3 signaling pathway-related proteins, including phosphorylated (p)-JAK1, p-JAK3 and p-STAT3. Subsequently, colivelin, an agonist of the JAK/STAT3 pathway, was used to investigate whether the effects of Tofa on intestinal I/R injury were mediated by this signaling pathway. The results showed that Tofa dose-dependently elevated cell viability compared with that in the OGD/R group. By contrast, Tofa attenuated cell apoptosis, which was coupled with upregulated Bcl-2 expression, downregulated cleaved-caspase-3 and downregulated cleaved-caspase-9 levels, in OGD/R-induced IEC-6 cells. Furthermore, the contents of ROS and MDA were significantly increased following exposure to OGD/R, which were accompanied by the decreased activity of SOD. These effects were reversed following cell treatment with Tofa. Consistently, Tofa intervention reduced the secretion levels of TNF-α, IL-6 and IL-1β in a dose-dependent manner. Additionally, Tofa markedly downregulated the phosphorylation levels of JAK1, JAK3 and STAT3 in OGD/R-induced IEC-6 cells. However, treatment with colivelin markedly reversed the inhibitory effects of Tofa on cell viability, cell apoptosis, oxidative stress and inflammation. Overall, the findings of the present study suggested that Tofa could protect against intestinal I/R injury by inhibiting the JAK/STAT3 signaling pathway, which may hold promise as a therapeutic agent for intestinal I/R injury.