The Hydro-alcoholic Extract of Achillea wilhelmsii C. Koch Ameliorates Acetic Acid-induced Ulcerative Colitis through TLR-4

Achillea wilhelmsii contains several anti-inflammatory and antioxidant phytochemicals, proposing protecting effect on inflammatory responses in autoimmune diseases such as inflammatory bowel diseases. However, its protective and anti-inflammatory activities against Ulcerative Colitis are unknown. This study intended to verify whether A. wilhelmsii is able to improve colitis via mediating inflammatory cytokines. Colitis was induced by intrarectal administration of acetic acid 4% in rats, except in sham group. Animals were treated with the hydro-alcoholic extract of A. wilhelmsii at concentrations of 50, 100, 200 mg/kg for 48 h. The other groups included the control (only treated with acetic acid), sham group (normal saline), and a standard group (Dexamethasone). Microscopic and histopathologic examinations were conducted in inflamed colonic tissue. Both macroscopic and microscopic examinations of colitis tissue were carried out. Tissue concentrations of interleukin (IL)-6 and tumor necrosis factor (TNF)-α were assessed by Eliza kits, while myeloperoxidase (MPO) was measured spectrophotometrically. mRNA expression of toll-like receptor (TLR)-4 was assessed in Real time-PCR. A. wilhelmsii ameliorated macroscopic and microscopic symptoms of induced colitis. The extract also downregulated pro-inflammatory mediators including IL-6, TNF-α, and MPO in the colon tissue . Substantial decline was recorded in mucosal TLR-4 expression, signifying considerable reduction of IL-6, and TNF-α production. This is the first report indicating that A. wilhelmsii abrogates experimental colitis through its anti-inflammatory activity, which in particular might be correlated with downregulation of TLR-4 expression.