Dipalmitoyl-phosphoethanolamine exhibits anti-colitis effect that involves down-regulation of IL-13 inflammatory cytokine by CD1d antagonism and iNK-T cells inactivation

Ulcerative colitis is a prevalent inflammatory bowel illness linked to immunological dysregulation, requiring suitable and effective treatment to inhibit its advancement. The goal of the current study was to investigate the potential anti-colitis effect of 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE), a CD1d-restricted antagonist of invariant natural killer T (iNK-T) cells with strong anti-inflammatory properties that have been previously documented. In order to assess the therapeutic efficacy of DPPE, colitis was induced in BALB/c mice through cutaneous pre-sensitization with 3% oxazolone (OXZ) then intra-colonic injection with 1% OXZ five days later. Colon length, disease activity index, and body weight changes were some of the assessed metrics. Besides, histological examination of specimens from the distal colon, assessment of CD1d mRNA expression by quantitative RT-PCR, and interleukin-13 (IL-13) inflammatory cytokine by ELISA were performed. DPPE significantly mitigated the disease activity index, body weight changes, histopathological features caused by OXZ, and nearly preserved the normal colon length. Additionally, it was obvious that DPPE substantially reduced the expression of CD1d and the inflammatory response in the colon, illustrated by markedly reduced inflammatory cells infiltration in colon sections and down-regulated colonic IL-13 content. Overall, as a well-defined CD1d-dependant inhibitor to iNK-T cells, DPPE could preserve most of the histological features in the colon; diminish colonic inflammatory cells infiltration, and IL-13 content which is one of the crucial contributors to OXZ-induced colonic inflammation. Thus, DPPE could be suggested as a potential efficacious candidate for anti-colitis therapy.