Effects Of Starvation On Autophagy And Oxidativestress In The Intestine Of Siniperca Chuatsi And Monopterus Albus

This study was conducted to determine the effect of starvation on oxidative stress,antioxidant system and autophagy in the intestinal of Chinese perch(Sinipercachuatsi)and swamp eel(Monopterusalbus).In the study of Chinese perch,the pathological changes,oxidative stress and autophagy in the intestinal of Chinese perch were analyzed at 0,2 and 5 days of starvation.In the study of swamp ee,the pathological changes,oxidative stress and autophagy in the intestinal of swamp ee were analyzed at 0,3,7,12 and 18 days of starvation.The main results of the present study are as follows:1.Effects of starvation on oxidative stress and autophagy in the intestinal of Chinese perch.After starvation treatment,the ROS,MDA content,antioxidant enzyme activity and the m RNA expression of related genes were analyzed in juveniles Chinese perch.The results showed that after 0,2 and 5d starvation,the contents of ROS and MDA significant increased(P<0.05),indicating oxidative stress was induced by starvation.After 2 days of starvation,the activities of antioxidant enzymes T-SOD,GST,GSH,GSH-PX and CAT significant increased(P>0.05).On the contrary,the activity of GR decreased significantly(P>0.05).After 5days of starvation,the activities of antioxidant enzymes T-SOD,GST,GSH,GSH-PX,CAT and GR were significantly decreased(P<0.05).Meanwhile,the m RNA expression of antioxidant genes(Mn SOD,Cu-Zn SOD,CAT,GST and GR)were significantly decreased(P<0.05),which consistent with the alternation of antioxidant enzymes activities.The m RNA expression of antioxidant related transcription factors(Keap1 and Nrf2)were decreased,indicating the induction of down-regulated activities of antioxidant enzymes by starvation attribute to transcriptional regulation.Moreover,short-term starvation induced autophagy and increase the expression level of autophagy genes.After 2 days of starvation,the expression of LC3 b decreased significantly(P<0.05).However,the expression of Beclin1 gene did not change significantly(P>0.05).After 5 days of starvation,LC3 b and Beclin1 were significantly increased(P<0.05).Meanwhile,the expression of key upstream factor m TOR of autophagy was increased after 2 days starvation,and decerased after 5 days starvation,which showed a opposite expression trend to LC3 b gene.The transmission electron microscopy analysis also showed the number of autophagosomes increased after short-term starvation.2.Effects of starvation on oxidative stress and autophagy in the intestinal of swamp eel.After starvation treatment,the level of ROS,MDA,antioxidant enzymes and related genes in the intestinal of swamp eel,mean while the expressions of autophagy-related genes were analyzed.The results showed that: the level of ROS and MDA has been the stage of up-trend after the starvation of(0,3,7,12,18)days(P<0.05).There were no significant difference was observed in ROS and MDA from 0 to 7 days and significantly increased after 7 days,which the starvation of 18 days had the highest values in the intestinal(P<0.05).It can cause oxidative stress and damage in organisms,hence affects the antioxidation level and it was strongly related with time.The antioxidant enzymes(GST、GSH-PX 、 CAT 、 GR)activity and antioxidant gene expression were both increased,while among them of T-SOD,GR activity were significantly increased from 0 to 7 days(P<0.05),but a significant decreased in the content of glutathione(P<0.05).After 7 days of starvation,the activities of antioxidant enzymes(T-SOD,GST,GSH-PX,CAT)and the content of GSH were significantly increased(P<0.05)and the results were consistent with mandarin fish,while the signaling molecule of Keap1 was decreased firstly and then increased.The expression of Keap1 was continuously drop from 0 to 7 days,meanwhile,7 days compared with 0 day were significantly decreased(P<0.05).Keap1 was starting to increase after 7 days with the prolonging of starvation,when the starvation of 18 days were significantly higher 0 day(P<0.05).As well as Nrf2 m RNA level was increased firstly and then decreased,which the starvation of 7 days had the highest values(P<0.05).The starvation of 3 and 7days compared with 0 day were significantly changes,however,the expression of Nrf2 was decreased significantly at 12 and 18 days(P<0.05).Meanwhile,there have been similar experiment results of LC3 b and Beclin1 m RNA level with mandarin fish by analyzing expressive regularity of autophagy and related genes.The m RNA level of LC3 b were no significant affected from 0 to 7 days(P>0.05),while the m RNA level were significantly increased with the prolonging to 7-18 days of starvation and the starvation of 18 days significantly higher than 12 days(P<0.05).The expression of m TOR was no significant affected to 3 days before(P>0.05)as well as significantly increased m RNA level(P<0.05).Moreover,the m RNA level were significantly decreased with the prolonging to 7-18 days of starvation that the starvation of 18 days significantly lower than 0 day(P<0.05).The expressions of Beclin1 were all ascending tendency that the expression had significantly difference at 3-7 days and 7-12 days.In addition,we can observe autophagosome by transmission electron microscopy that the autophagosome was increased with the increase of time in the intestinal.