Protective Effects of Xyloglucan in Association with the Polysaccharide Gelose in an Experimental Model of Gastroenteritis and Urinary Tract Infections

Abstract

Acute infectious gastroenteritis (GE) and urinary tract infection (UTI) are common diseases and are normally perceived as mild and limiting illnesses. Xyloglucan is a natural plant polymer with protective barrier properties, also known as “mucosal protectors”, which is the main ingredient of medical devices developed for the management of different diseases, such as gastrointestinal diseases, urinary tract infections, or respiratory allergic diseases. The aim of this study was to evaluate the protective effect of xyloglucan in association with gelose (also called agar) in an experimental model of bacterial GE and UTI in rats. Two kinds of infection were induced by oral administration of Salmonella enterica and Enterococcus hirae for three days. Two days before the bacterial administration, preventive oral treatment with xyloglucan + gelose (10 mg/kg + 5 mg/kg) was performed daily until the seventh day. Twenty-four hours after the last treatment, rats were sacrificed and urinary tracts and intestines for different analysis were collected. The results showed that xyloglucan plus gelose was able to reduce intestinal morphological changes (p < 0.05 for both), tight junctions (TJ) permeability (p < 0.001 for both), and neutrophil infiltration (p < 0.05 for both) induced by bacterial infections, highlighting its barrier proprieties. Moreover, the compound reduced the number of bacterial colonies in the urinary tract favoring elimination by feces. The results obtained in the present study suggest that the protective barrier properties of xyloglucan plus gelose allow the prevention of GE and UTI in models of infections in rats.

Keywords: gastroenteritis; gelose; urinary tract infection; xyloglucan.

Figure 1

(A) The sham group; (B) Histological examination of intestine showed transmural necrosis, edema, and leukocyte infiltration in the submucosa of intestine following S. enterica inoculation compared to sham group; (C) Xyloglucan + gelose treatments significantly reduced the degree of tissue injury; and (D) The histological score. Values are means ± SEM of 10 animals for each group. *** p < 0.001 vs. Sham, ^# p < 0.05 vs. S. enterica.

Figure 2

(A) The sham group; (B) Intestine from E. hirae inoculated rats showed transmural necrosis, edema, and leukocyte infiltration in the submucosa of tissue compared to the sham group; (C) Xyloglucan + gelose treatments appreciably reduced the degree of tissue injury; and (D) The histological score. Values are means ± SEM of 10 animals for each group. *** p < 0.001 vs. Sham, ^# p < 0.05 vs. E. hirae.

Figure 3

(A) MPO activity in intestine homogenates was significantly elevated from S. enterica inoculated rats. A significant decreasing in MPO activity was observed in intestine from rats treated with xyloglucan + gelose (10 mg/kg + 5 mg/kg); and (B) The same situation was observed for E. hirae inoculated rats. Pictures were captured at 10× magnification. Figures are representative of at least three separate experiments. Values are means ± SEM of 10 animals for each group. (A) ** p < 0.01 vs. Sham, ^# p < 0.05 vs. S. enterica. (B) ** p < 0.01 vs. Sham and ^# p < 0.05 vs. E. hirae.

Figure 4

Immunostaining for ZO-1 and occludin expression in sham mice ((A) and (D) respectively); positive staining for ZO-1 and occludin following S. enterica infection ((B) and (E) respectively) and mice treated with xyloglucan + gelose ((C) and (F) respectively). (G) Densitometric analysis. Data are representative of at least three separate experiments. Images are representative of all animals in each group. Pictures were captured at 10× magnification (scale bar = 100 μm). Figures are representative of at least three separate experiments. Values are means ± SEM of 10 animals for each group. (ZO-1). *** p < 0.01 vs. Sham, ^### p < 0.001 vs. S. enterica; (occludin) *** p < 0.001 vs. Sham and ^### p < 0.001 vs. S. enterica.

Figure 5

Immunostaining for ZO-1 and occludin expression in sham mice ((A) and (D) respectively). Positive staining for ZO-1 and occludin following E. hirae infection ((B) and (E) respectively) and mice treated with xyloglucan + gelose ((C) and (F) respectively). (G) Densitometric analysis. Data are representative of at least three separate experiments. Images are representative of all animals in each group. Pictures were captured at 10× magnification (scale bar = 100 μm). Values are means ± SEM of 10 animals for each group. Figures are representative of at least three separate experiments. (ZO-1) *** p < 0.01 vs. Sham, ^### p < 0.001 vs. E. hirae; (occludin) *** p < 0.001 vs. Sham and ^### p < 0.001 vs. E. hirae.

Figure 6

(A,B) Urinary pH values were recorded every day for eight days; and (A1,B1) Urine volume was collected every day for eight days. Values are means ± SEM of 10 animals for each group. Figures are representative of at least three separate experiments.

Figure 7

The number of bacteria recovered from bladder, urethra, and feces of rats killed eight days after S. enterica inoculation. Seven days after S. enterica inoculation, all rats had positive bladder and urethra cultures (bladder and urethra graphs). The number of bacteria recovered from the bladder showed a tendency to decrease in both the bladder and urethra after xyloglucan + gelose treatment (bladder and urethra graphs). S. enterica was significantly eliminated from the urinary tract but not from feces following xyloglucan + gelose treatments (feces graphs). Figures are representative of at least three separate experiments. Values are means ± SEM of 10 animals for each group.

Figure 8

Rats infected with E. hirae showed positive bladder and urethra cultures while the treatment with xyloglucan + gelose significantly reduced the bacteria titers in the bladder but not in urethra (bladder and urethra graphs). Moreover, following xyloglucan + gelose treatment, E. hirae was significantly eliminated from the feces (feces graphs). Values are means ± SEM of 10 animals for each group. Figures are representative of at least three separate experiments. (Bladder) *** p < 0.01 vs. Sham, ^### p < 0.001 vs. E. hirae; (feces) ** p < 0.01 vs. Sham and ^# p < 0.05 vs. E. hirae.

Figure 9

Schematic representation of the S. enterica and E. hirae infection model.