Role of tumor necrosis factor-α in the pathogenesis of indomethacin-induced small intestinal injury in mice

Abstract

Abstract. The pathogenesis of small intestinal damage caused by non-steroidal anti-inflammatory drugs (NSAIDs) such as indomethacin is still unclear. For this reason, there is currently no therapeutic strategy for ameliorating such damage. On the other hand, molecular treatment strategies targeting tumor necrosis factor (TNF)-α exert beneficial effects on intestinal lesions in patients with inflammatory bowel disease (IBD). To clarify the participation of TNF-α in NSAID-induced small intestinal damage, we investigated the effects of indomethacin administration in mice with targeted deletion of the TNF-α gene. Indomethacin (10 mg/kg) was administered subcutaneously to male C57BL/6 (wild-type: WT) mice and TNF-α-deficient (TNF-α -/-) mice to induce small intestinal damage. The ulcer score, the tissue-associated myeloperoxidase (MPO) activity as an index of neutrophil infiltration, and the expression of keratinocyte chemoattractant (KC) mRNA in the small intestinal mucosa were measured. In addition, we performed a TUNEL assay to evaluate indomethacininduced apoptosis of intestinal epithelial cells and measured the expression of caspase-3 protein and Bcl-2 mRNA. The ulcer score, MPO activity, and expression of KC mRNA were significantly increased after indomethacin administration. These increases were significantly inhibited in TNF-α -/-mice compared with WT mice. Apoptotic cells were observed by the TUNEL assay in the area of the ulcerative lesion, and they were significantly fewer in TNF-α -/-mice compared with WT mice. The expression of cleaved caspase-3 protein was induced by indomethacin administration, and significantly inhibited in TNF-α -/-mice compared with that of WT mice. The expression level of Bcl-2 mRNA in indomethacin-treated TNF-α -/-mice was significantly higher than that in WT mice. TNF-α plays an important role in the pathogenesis of indomethacin-induced small intestinal damage. These results suggest that TNF-α could become a new therapeutic target for NSAID-induced small intestinal damage.

Pharmacological inhibition of soluble epoxide hydrolase or genetic deletion reduces diclofenac-induced gastric ulcers

“…Specifically, NSAID-induced small intestinal and gastric ulcers were reduced by a TNF-α synthesis inhibitor [54, 55]. Similarly, indomethacin-induced inflammatory bowel disease was alleviated by the antibody to TNF-α or gene deletion of TNF-α [56, 8]. TNF-α mediated ulceration involves apoptosis [57].…”

“…In addition to PGE 2 , multiple other biological pathways seem responsible for the formation of NSAID-induced ulcers [7–11]. While NSAIDs suppress inflammation, NSAID-induced ulcers are associated with increases in the levels of inflammatory markers such as TNF-α and IL-6 [8, 12]. Although a downstream consequence of COX-2 activity, TNF-α is proposed to play an important role in ulcer pathways activated by prolonged use of NSAID.…”

“…Although a downstream consequence of COX-2 activity, TNF-α is proposed to play an important role in ulcer pathways activated by prolonged use of NSAID. Anti-TNF-α antibodies for example significantly decrease necrotic and apoptotic lesions associated with ulcers in rats [13, 14] and TNF-α knockout mouse is more resistant to NSAID-induced ulceration [8]. …”

Bacterial β-glucuronidase inhibition protects mice against enteropathy induced by indomethacin, ketoprofen or diclofenac: mode of action and pharmacokinetics

“…For the toxicopathology studies, 5–11 mice per treatment group were used, and for the kinetic study, nine mice per treatment group (three mice for identical time points). The doses for the three NSAIDs (DCF, 60 mg/kg; indomethacin, 10 mg/kg; ketoprofen, 100 mg/kg) were selected from previously published studies (Fukumoto et al, 2011; Ramirez-Alcantara et al, 2009); after correction with the interspecies dose scaling factor (× 12 for mouse) (Kirman et al, 2005), they are comparable to the human therapeutic doses. The intraperitoneal route was selected to ensure maximal absorption and to minimize drug–drug interactions during administration; previous data have shown that DCF administered either intraperitoneally or orally produced a similar extent of enteropathy in rats, due to the critical role of hepatobiliary excretion of glucuronoconjugates (Seitz & Boelsterli, 1998).…”

Understanding and Modulating Mammalian-Microbial Communication for Improved Human Health

“…A major proinflammatory cytokine that increases via TLR4 signaling following indomethacin treatment is tumor necrosis factor-α (TNF-α) (144). The causal involvement of TNF-α in the development of enteropathy has been convincingly demonstrated with anti-TNF-α antibodies or TNF-α-null mice, as both types of mice are protected against indomethacin-induced injury (145, 146). Similarly, intraperitoneal administration of antineutrophil antibody attenuates indomethacin-induced enteropathy (147), providing evidence for a causal role of PMNs in the pathogenesis of NSAID enteropathy.…”