Protective effect of royal jelly in 2,4,6 trinitrobenzene sulfonic acid-induced colitis in rats

OBJECTIVES In the present study, we evaluated immunological and immunomodulatory properties of royal jelly (RJ) in 2,4,6 trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats. MATERIALS AND METHODS Eighteen adult female Wistar albino rats were divided into three groups of six animals each: a control group that received only saline solution, a TNBS-induced colitis group, and a TNBS-colitis+RJ group that received 250 mg/kg/day of RJ for seven days before the induction of colitis, following by the same treatment for an additional seven days. At the end of the experiment, cardiac blood and colon samples were obtained under deep anaesthesia from the animals in all groups. Serum interleukin-1β (IL-1β), tumour necrosis factor-alpha (TNF-α) and IL-10 levels were analyzed with an enzyme-linked immunosorbent assay (ELISA). Five-micrometre-thick sections were stained with haematoxylin-eosin (H&E) for microscopic evaluations. For immunohistochemical evaluations, the paraffin sections were stained with anti-CD3 (cluster of differentiation), anti-CD5, anti-CD8 and anti-CD45. RESULTS The results showed that the oral RJ treatment inhibited proinflammatory cytokines, IL-1β and TNF-α secretion, while increasing anti-inflammatory cytokine IL-10 production in the TNBS-induced colitis+RJ group compared with the colitis group not treated with RJ. The colitis was not as severe in the colitis+RJ group, with ulcerative damage, weight loss and inflammatory scores suggesting that impaired CD3-, CD5-, CD8- and CD45-positive T cell immune responses likely mediated the anti-inflammatory effect. CONCLUSION The antioxidant and anti-inflammatory properties of RJ protected colon mucosa against TNBS-induced colitis in rats orally treated with RJ.