Intestinal injury can be effectively prevented by Dunaliella salina in gamma irradiated rats

Abstract

Dunaliella salina (D. salina) is one of the most common microalgae that is used as human food. It is isolated from the salty lakes in El-Fayoum and Lake of Bardawil-Sinai in Egypt and can withstand very high concentrations of salt: The potentiality of D. salina, a unicellular biflagellate green alga to protect against intestinal injury induced after radiation exposure was studied. D. salina was given orally in doses of 100 and 200 mg/kg to male Wistar rats for 5 days before exposure to 6 Gray (Gy) gamma radiation and continued for a further two days. Rats were sacrificed 24 h later and intestinal segments were dissected out. One segment was examined histologically and another was used to prepare homogenates to assess relevant biochemical parameters reflecting intestinal injury. Radiation exposure led to a rise in the histological damage score, an increase in tissue tumor necrosis factor (TNF-α), interleukin (IL-1β) and thiobarbituric acid reactive substances (TBARS) but a reduction in tissue reduced glutathione (GSH) and in serum citrulline. Pretreatment with either dose of D. salina effectively reduced the severity of intestinal mucositis induced by gamma radiation.

Keywords: Biochemistry.

Fig. 1

Histological micrograph of the jejunum of normal rats showing normal structure of mucosa, submucosa, musculosa and serosa. Note the long intestinal villi (H&E x 100).

Fig. 2

Histological micrograph of the jejunum of irradiated rats. (A) showing shortening and focal denudation of intestinal villi (small arrow), activation of glandular epithelium (large arrow) and focal inflammatory cell infiltration in lamina propria (arrow head); (B) showing activation of glandular epithelium (small arrow), inflammatory cell infiltration in lamina propria (large arrow) and hemorrhage in lamina propria (arrow head) (H & E x 100).

Fig. 3

Histological micrograph of the jejunum of rats treated orally with D. salina (A) 100 mg/kg, showing slight activation of glandular epithelium (small arrow) with few inflammatory cells infiltration in lamina propria (large arrow); (B) 200 mg/kg, showing slight activation of glandular epithelium (H & E X 100).

Fig. 4

Semi-quantitative histological assessment of radiation induced intestinal damage in rats after exposure to 6 Gy as influenced by D. salina administration. Values are the sum of median scores for ten histological criteria (see text). * indicates p ≤ 0.05 compared to normal; ‡ indicates p ≤ 0.05 compared to irradiated rats.

Fig. 5

Effect of D. salina on the level of GSH (mg/g tissue) and TBARS (nmol/g tissue) in the jejunal tissue of irradiated rats. All values are expressed as means ± standard error mean (SEM). ^@ p ≤ 0.05 compared to normal, ‡p ≤ 0.05 compared to irradiated animals.

Fig. 6

Effect of D. salina on the level of TNF-α and IL-β in the jejunal tissue of irradiated rats. All values are expressed as means ± standard error mean. ^@p ≤ 0.05 compared to normal, ‡p ≤ 0.05 compared to irradiated rats.

Fig. 7

Effect of D. salina on the level of citrulline in the serum of irradiated rats. All values are expressed as means ± standard error mean. ^@p ≤ 0.05 compared to normal, ‡p ≤ 0.05 compared to irradiated animals.