Colo‐Protective Effects of Pentoxifylline Alone or in Combination With Mesalamine in Colitis Through Sphingosine Kinase 1/Sphingosine 1 Phosphate, and Zonula Occuldin 1 Pathways: New Molecular Approach

Multiple signaling pathways have been implicated in the pathogenesis of ulcerative colitis (UC), including Sphingosine Kinase 1 (SPHK)/Sphingosine-1-Phosphate (S1P), AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR)/NLR family pyrin domain-containing 3 (NLRP3), zonula occludens-1 (ZO-1), and signal transducer and activator of transcription 3 (STAT3). We aimed to investigate the Colo protective and anti-ulcerative effects of pentoxifylline (PTX) in a rat model of UC. Colitis was induced by intracolonic administration of 2 mL of 3% (v/v) acetic acid (AA). Thirty-five rats were randomly assigned to five groups (n = 7 each): normal control, colitis, mesalamine, PTX, and a combination of PTX plus mesalamine. Disease activity was assessed using the disease activity index, colon weight and length measurements, histological examination, and immunohistochemical detection of caspase-3. Colonic tissue homogenates were analyzed for interleukin-6 (IL-6), S1P, SPHK, mTOR, heme oxygenase-1 (HO-1), nuclear factor erythroid 2-related factor 2 (Nrf2), AMPK, and STAT3 levels. Gene expression of ZO-1 and NLRP3 was also evaluated. Intracolonic AA induced marked functional, biochemical, and inflammatory damage to colonic tissue. Treatment with PTX, mesalamine, or their combination significantly attenuated these effects. Specifically, all treatments reduced levels of IL-6, S1P, SPHK, mTOR, STAT3, NLRP3, and caspase-3, while increasing levels of ZO-1, HO-1, Nrf2, and AMPK. The combination treatment group exhibited near-complete restoration of normal colonic architecture, characterized by intact crypt morphology and minimal fibrosis in the lamina propria. PTX attenuated inflammation, apoptosis, and oxidative stress in colitis, supporting its potential as an adjuvant therapy in UC management.