Quercetin prevents small intestinal damage and enhances intestinal recovery during methotrexate-induced intestinal mucositis of rats

Abstract

Background: Gastrointestinal mucositis occurs as a consequence of cytotoxic treatment. Quercetin (QCT) is a bioflavonoid that exerts significant antioxidant activity and anti-inflammatory as well as anti-malignancy properties.

Objective: To evaluate the effects of oral QCT consumption in preventing intestinal mucosal damage and stimulating intestinal recovery following methotrexate (MTX)-induced intestinal damage in a rat model.

Design: Male Sprague-Dawley rats were divided into four groups: Control Group A (CONTR) - rats were treated with 2 cc of saline given by gavage for 6 days. Group B (CONTR-QCT) - rats were treated with QCT (100 mg/kg in 2 ml saline) given by gavage 3 days before and 3 days after intraperitoneal (IP) injection of saline. Group C (MTX) - rats were injected a single dose (25 mg/kg) of MTX IP. Group D (MTX-QCT) rats were treated with QCT (similar to Group B) 3 days before and 3 days after IP MTX injection. Intestinal mucosal parameters (bowel and mucosal weight, mucosal DNA and protein content, and villus height and crypt depth), enterocytes proliferation, and enterocyte apoptosis degree were investigated at sacrifice on the 4th day after MTX or saline injection.

Results: Administration of QCT to MTX-treated rats resulted in: (1) significant decrease in intestinal injury score, (2) significant increase in intestinal and mucosal weight in jejunum and ileum, (3) increase on the protein content of the ileum, (4) increase in the villus height in the ileum, (5) increase of crypt depth of jejunum and ileum, and (6) increase in cell proliferation in the jejunum and ileum compared to MTX-nontreated group.

Conclusions: Administration of QCT prevents intestinal damage and improves intestinal recovery following MTX-induced intestinal damage in a rat. We surmise that the effect of QCT is based on induction of cell proliferation in the crypt rather than inhibition of apoptosis.

Keywords: chemotherapy; enterocyte apoptosis; enterocyte proliferation; methotrexate; mucositis; quercetin.

Fig. 1

Effects of MTX and quercetin on body weight changes. Values are mean ± SEM. CONTR, control; MTX, methotrexate; QCT, quercetin. *p < 0.05 MTX and MTX-QCT versus CONTR rats.

Fig. 2

Effects of MTX and QCT on intestinal injury score and microscopic appearance. The following parameters were investigated: (A) Degeneration of surface and crypt epithelium; (B) degeneration of villus structure, vacuolization in the surface epithelium; and (C) inflammatory cell infiltration, and bleeding and edema in the lamina propria. For each criterion, a score was given using a semiquantitative scale as follows: 0 = none, 1 = mild, 2 =moderate, 3 = severe, giving a maximum possible score of 9 for each segment. Values are mean ± SEM. CONTR, control; MTX, methotrexate; QCT, quercetin. *p < 0.05 MTX and MTX-QCT versus CONTR rats; ^†p < 0.05 MTX-QCT versus MTX.

Fig. 3

Effects of MTX and oral QCT on cell proliferation and apoptosis. The number of BrdU-labeled cells in 10 well-oriented, longitudinal crypts per section from each rat was determined using light microscopy. Identification of apoptotic cells was performed using immunohistochemistry for Caspase-3. The apoptotic index is expressed as the percentage of apoptotic cells per 10 villi. Values are mean ± SEM. CONTR, control; MTX, methotrexate; QCT, quercetin. *p < 0.05 MTX and MTX-QCT versus CONTR rats; ^†p < 0.05 MTX-QCT versus MTX.

Fig. 4

Effects of MTX and oral QCT on proliferation (p-ERK) and apoptosis (caspase-3)-related proteins (Western blot). Results are calculated as the ratio to tubulin and are expressed as a percentage of control animals. CONTR, control; MTX, methotrexate; QCT, quercetin. *p < 0.05 MTX and MTX-QCT versus CONTR rats; ^†p < 0.05 MTX-QCT versus MTX.