The Study Of 3-Methyladenine On The Influence Of Autophagy In Intestinal Epithelial Cells Of Rats Rapidly Ascending To High Altitude Areas

Objective: To investigate the influence of 3-Methyladenine(3-MA) as an autophagy inhibitor on the level of autophagy and the injury extent of intestinal epithelial cells caused by hypobaric hypoxia in rats of plateau hypoxia model.Methods: Fifty healthy male Wister rats weighing between 180-280 g and aging between 6-9 weeks were used as the research materials. All rats were randomly divided into five groups: group A is plain control group, group B is 24 h plateau model group, group C is 3-MA treated 24 h plateau group, group D is 48 h plateau model group and group E is 3-MA treated 48 h plateau group. All rats were treated by the model of hypobaric hypoxia in decompression chamber of 5000 m high attitude except rats in group A. We chose the best inhibitory concentration of 3-MA in advance. Then group C and E were administered the best concentration of 3-MA(20mg/kg, dissolved in 1 ml 0.9% normal saline), while group A, B and D were given 1 ml 0.9% normal saline by intraperitoneal injection half an hour before the model was established. After 3-MA injection, behavioral change of rats was observed, and the intestinal tissue injury was analyzed by hematoxylin-eosin stain ing, and the expressions of autophagy-related protein LC-3 and Beclin-1 were detected by immunohistochemistry and RT-PCR.Results:(1) 20 mg/kg of 3-MA in concentration had an prominent effect of inhibit ing autophagy in intestinal epithelial cells;(2) The scores of intestinal t issue pathological damage: the rats’ intestinal tissue of group A were almost normal(1.1±0.3). There was a significant difference among the rats’ intestinal tissue of group B, C, D, E in pathological damage(3.1±0.6, 4.5±0.5, 2.6±0.5, 3.8±0.4) comparing with group A(P<0.05); scores of rats’ intestinal pathological damage were signif icantly increased after 3-MA was injected(P<0.01);(3) The transmission electron microscopy indicated that autophagosomes of intestinal epithelial cells could be seen in the model groups(group B and D) and the numbers of autophagosomes in group C and E were significantly reduced;(4) RT-PCR and immunohistochemistry suggested that the protein and mRNA expressions of LC-3 and Beclin-1 in the model groups were significantly increased comparing with the plain group(P<0.05); the protein and mRNA expressions of LC-3 and Beclin-1 in 3-MA groups were significantly decreased comparing with the corresponding model groups(P<0.01).Conclusion:(1) 3-MA may aggravated the intestinal epithelial cell’s damage by reducing autophagy in high alt itude areas;(2) Autophagy may play an important protective role in intestinal epithelial cell damage caused by plateau hypoxia.