Protective Role of Rheum Tanguticum Polysaccharide 1 in Radiation- induced Intestinal Mucosal Injury

Abstract

The protective effects of Rheum tanguticum polysaccharide 1 (RTP1), which is extracted from the Chinese traditional medicine Rheum tanguticum, on radiation-induced intestinal mucosal injury was investigated. Rat intestinal crypt epithelial cells (IEC-6 cells) and Sprague-Dawley rats were each divided into control, irradiated and RTP1-pretreated irradiated groups. After irradiation, cell survival was determined by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide). assay, and the intracellular reactive oxygen species (ROS) was detected by fluorescent probe method. Apoptosis was observed by acridine orange staining, and cell cycle was analysed by flow cytometry. Histological analysis of the rat intestinal mucosa was conducted by haematoxylin and eosin staining. Irradiation at 8 Gy(Gray) decreased cell survival rate to only 54%, significantly increased intracellular ROS levels and induced apoptosis. RTP1 pretreatment significantly inhibited cell death, reduced the formation of intracellular ROS and partially inhibited apoptosis. Irradiation markedly reduced the height and quantity of rat intestinal villi, but it could be antagonised by RTP1 pretreatment. RTP1 can promote the recovery of intestinal mucosa damage, possibly by inhibiting radiation-induced intestinal epithelial apoptosis and intracellular ROS production.

Keywords: Ionising radiation; Polysaccharide; Radioprotection; Rheum tanguticum; Small intestine.

Figure 1

Effect of RTP1 on cell viability. *P < 0.05 vs control; ^#P < 0.05 vs Vehicle+IR.

Figure 2

Laser confocal scanning microscope image of DCF fluorescence in cells of different groups. A: Control; B: Vehicle+IR; C: RTP₁ +IR.

Figure 3

Effect of RTP₁ on IEC-6 cell apoptosis identified by acridine orange staining.

Figure 4

Effects of RTP1 on IEC-6 cell cycle progression. A: Control; B: Vehicle+IR; C: RTP₁ +IR.

Figure 5

Representative images showing height of villi and crypt cell survival in the intestinal circumference of different groups. A: Control; B: Physiological saline+IR; C: RTP₁ +IR.