Learning-memory Ability Decline In Rats Caused By Chronic Unpredictable Mild Stress Was Related To The Excessive Autophagy Mediated By CaMKKβ/AMPK Signaling Pathway

Objective:(1)To researching the impact of chronic unpredictable mild stress on learning-memory ability,CaMKK?/AMPK signaling pathway and autophagy in rat hippocampus CA1 area.(2)To investigate the effect of CaMKK?/AMPK signaling pathway on learning-memory ability and autophagy in rat hippocampus of chronic unpredictable mild stress rats.(3)To reveal the possible mechanism of learning and memory decline caused by chronic unpredictable mild stress in rat.Methods:40 fine and male SD rats were stochasticaly distributed into four groups:healthy control group(control group);chronic unpredictable mild stress group(CUMS group);CUMS+STO-609 group(STO-609 group);CUMS+ Compound C group(Compound C),10 rats in each group.Except for the control group, the other three group were dealed with chronic stress for four weeks. From the first day of chronic stress, CUMS group was treated with 10 μl PBS(solvent),STO-609 group was treated with 10 μl STO-609(CaMKK? inhibitor) and Compound C groud was treated with 10 μl Compound C( AMPK inhibitor). once a day, The intracerebroventricular injection speed was controlded in 0.6 ul/min for continuous four weeks. the first day of fourth week stressing,Each group of rats start performing Morris water maze experiment.After Water maze experiment was finished, first of all, each rat was detached tail for blood,The expression level of GCs was tested by Radioimmunoassay method. And then cut off the head to take out the hippocampal tissue. the organization tissue of hippocampal CA1 area was observed by HE. By the methods of TUNEL, the apoptosis of hippocampal CA1 was observed. By using transmission electron microscope,the number of autophagosome of hippocampal CA1 area were observed. With the help of technology of Western-Blot respectively,The expression level of CaMKK?, P-AMPK Beclin1, LC3 and p62 was measured.Results:(1)Compared with the control group,CUMS result in a apparently greater increase in plasma corticosterone level. And the difference was statistically significant(P<0.05).There were no significant differences in blood corticosterone levels of the STO-609 group or Compound C group Compared with the CUMS group.(P>0.05).(2) In CUMS group, the escape latency was deferred Compared with the control group, the difference was remarkable significant(P<0.05).However, In the STO-609 group or Compound C group,Compared with the CUMS group, The escape latency of rats was apparent curtate,the difference was remarkable significant(P<0.05).(3)In the CUMS group, compared with the control group, the number of the CA1 cells was obviously decreased.Cells arranged irregularly and the edge of many cells was unclear., the difference was statistically significant(P<0.05).which was observed by the methods of HE. But in the STO-609 group or Compound C group. The number of CA1 cells was Significantly increased compared with the control groups,the difference was remarkable significant(P<0.05).(4)In the CUMS group, The number of the apoptosis of cells was apparent rasied Compared with the control group,the difference was remarkable significant(P<0.05).in the STO-609 group or Compound C The total number of the apoptosis of cells was Significantly decreased compared with the CUMS group, the difference was statistically significant(P<0.05). that was observed by TUNE.(5)In CUMS group,The number of autophagosome in hippocampus CA1 region was remarkable increased compared with control group(P<0.05), In the STO-609 group or Compound C,but, The number of mitochondrial swelling and autophagosome in hippocampus CA1 region was obviously decreased compared with the CUMS group, the difference was statistically significant(P<0.05).that was observed by transmission electron microscope.(6) In CUMS group, the expression level of CaMKK?,P-AMPK, Beclin1, LC3-Ⅱand the ratio of LC3-Ⅱ/Ⅰ were apparently elevate compared with the control group,the difference was remarkable significant(P<0.05).But the expression of p62 were significantly declined(P<0.05). In the STO-609 group or Compound C group, The expression level of P-AMPK, Beclin1, LC3-Ⅱand the ratio of LC3-Ⅱ/Ⅰwere apparently decreased Compared with the CUMS group(p<0.05),the expression of p62 were significantly higher(P<0.05),But the expression of CaMKK? in STO-609 group or Compound C group were not statistically significant(P>0.05).Conclusion:(1)CUMS can cause learning-memory ability decline,CaMKK?/AMPK signaling pathway activated and intemperate autophagy of the cells of hippocampus CA1 region.(2) learning-memory ability decline in rats caused by chronic unpredictable mild stress was ralated to the excessive autophagy mediated by CaMKK?/AMPK signaling pathway.