Quercetin-loaded microcapsules modulate intestinal serotonin, cell proliferation, and mucosa architecture in adjuvant-induced arthritis.

We investigated whether the effect of treatment with quercetin-loaded microcapsules 10 mg/kg promotes anti-inflammatory action and prevents damage to the intestinal wall in the jejunum of rats with adjuvant-induced arthritis. Thirty Holtzman rats were distributed into 5 groups: C (control), control administered with quercetin-loaded microcapsules 10 mg/kg (CQ), adjuvant-induced arthritis (AIA), adjuvant-induced arthritis administered with ibuprofen 17.5 mg/kg (AI) and adjuvant-induced arthritis administered with quercetin-loaded microcapsules 10 mg/kg (AQ). After 60 days, the jejunums were collected for histological and immunohistochemical techniques. CD20+ , CD45+, CD68+, CD206+, 5-HT+ cells, mast cells, intraepithelial lymphocytes, goblet cells, intestinal wall morphometry and cell proliferation were evaluated. AIA triggered intestinal inflammation assessed by the increase in immune cells. AIA also caused hypertrophy of the intestinal wall, evidenced by the increase in the height and width of the villi, crypts depth, mucosa height, total intestinal wall and increased cell proliferation in the crypts. Quercetin-loaded microcapsules in rats with AIA (AQ) showed anti-inflammatory action and prevented depletion of goblet cells, the widening of the villi, crypts depth, increased 5-HT+ cells and increased cell proliferation. Ibuprofen (AI group) showed anti-inflammatory action, prevented damage to the intestinal wall, goblet cells and 5-HT+ cells. In CQ, increased macrophages, intraepithelial lymphocytes, cell proliferation, and intestinal wall thickness. Chronic AIA caused inflammation, intestinal wall alteration and increased 5-HT+ expression in the mucosa. Quercetin-loaded microcapsules showed beneficial effects on the alterations in the intestinal mucosa architecture caused by AIA, being a promising antioxidant and anti-inflammatory compound for the treatment and prevention of arthritis progression.