Regulation Mechanism Of Escitalopram On The Expression Of Endoplasmic Reticulum Stress Related Genes In The Depression Model Rats

Objective: To explore the regulation mechanism of Escitalopram?N-acetylcysteine and Metoprolol on the expression of apoptosis rate in cerebral cortex and hippocampus and the expression of endoplasmic reticulum stress the PERK pathway related genes in the depression model rats. Methods: Forty-five sexually mature male SD rats were used as subjects. The rats were randomly divided into 5groups as following: 1. Group C: control +normal saline group(10 ml/kg/d),2. Group D: depression+saline group(10 ml/kg/d), 3. Groups with drugs:(1) Group X:depression+Escitalopram group(10 ml/kg/d),(2) Group M: depression+Metoprolol group(10 ml/kg/d),(3)Group N: depression+N-acetylcysteine group(125mg/kg/d)?Chronic unpredictable mild stress(CUMS) combined with isolation was used to make depression animal model, and drug groups were intraperitoneal injected corresponding drug for 4 weeks from the first day of making depression animal model every morning 8:00-9:00 am simultaneously. Control group and depression group were intraperitoneal injected with normal saline. Open-field test and sugar consumption experiment were tested on before the experiment and the 28 th day of the experiment. Flow cytometry Annexin V-PI double staining was used to detect the apoptosis rate in cerebral cortex and hippocampus of rats. Transmission Electron Microscope was used to observe the change of the morphology, endoplasmic reticulum and mitochondria of cortex and hippocampus in rats. Quantitative Real-time PCR and Western blot were used to observe the gene and protein expression of calmodulin-dependent protein kinases or CaM kinases ?(CaMK?)?protein kinase like endoplasmic reticulum kinase(PERK) ? extraeellular signal regulated kinase(ERK1/2) ? phosphorylated extracellular signal regulated protein kinase 1/2(p-ERK1/2) ? c-Jun N-terminal kinase(JNK) ? phosphorylated c-Jun N-terminal kinase(p-JNK). Results:(1) Behavior score(horizontal movement score + vertical movement score) of open-field test and the percentage of sugar consumption experiment in each group rats evaluated before the chronic unpredictable mild stress(CUMS) and isolation had no significant difference(P > 0.05). After chronic unpredictable mild stress and isolation,the behavior score and percentage of sugar consumption in group D were decreased significantly contrast to the group C?group X?group M?group N separately(each P<0.05).(2)The apoptosis rate in cerebral cortex and hippocampus of group D was significantly increased compared with the group C(P<0.05). The apoptosis rate in cerebral cortex of group X?group M?group N was significantly decreased compared with group D separately(each P<0.05), and the effect was X>M,N>M. The apoptosis rate in hippocampus of group X and group N was significantly decreased compared with group D separately(each P <0.05), and the effect was X>M,N>M.(3)Electron microscopy showed that nerve cells and organelles of cerebral cortex and hippocampus in control group were integrity, structure clearly; Nerve cells and organelles of cerebral cortex and hippocampus in depression group occurred fuzzy structure?disorder arrangement and decreased quantity. Nerve cells of cerebral cortex and hippocampus in other drug treatment model group varied between control group and depression group.(4)Western blot showed that the protein expression of ERK?p-ERK?JNK?p-JNK?PERK of cerebral cortex in each group rats had no significant difference(P > 0.05). The protein expression of CaMKII in group D was increased compared with group C in rat cerebral cortex(P<0.05). The protein expression of ERK?JNK?PERK of cerebral hippocampus in each group rats had no significant difference(P>0.05). The protein expression of p-ERK in group D was decreased compared with group C in rat cerebral hippocampus(P<0.05). The protein expression of p-ERK in group X and group N was increased compared with group D separately in rat cerebral hippocampus(P <0.05).The protein expression of p-JNK in group D was increased compared withgroup C in rat cerebral hippocampus(P<0.05). The protein expression of CaMKII in group D was increased compared with group C in rat cerebral hippocampus(P<0.05).(5)Real-time PCR showed that the gene expression of ERK?JNK?PERK in group D compared with group C separately in rat cerebral cortex and hippocampus had no significant difference(P> 0.05). The gene expression of ERK?JNK ?PERK and CaMKII in cerebral cortex and hippocampus in group X ? group M and group N compared with group D separately in rat cerebral cortex and hippocampus had no significant difference(P > 0.05). Conclusion:(1) Escitalopram, N-acetylcysteine,Metoprolol can improve the abnormal behavior and anhedonia of depression group rats.(2) The apoptosis rate in cerebral cortex and hippocampus cells increase in depression model rats. Escitalopram?N-acetylcysteine?metoprolol can reduce the apoptosis rate of cerebral cortex and hippocampus in depression model rats and the effect is Escitalopram>Metoprolol;N-acetylcysteine>Metoprolol.(3)Hippocampal and cortical neurons of depression model rats appear to have different degrees of disorder?fuzzy structure. Mitochondria and other organelles occur fuzzy structure and the number of organelles decreased. Escitalopram, N-acetylcysteine, Metoprolol can reduce the changes of cortical and hippocampal neuronal cells and organelles in depression model rat.(4) The protein expression of p-JNK in the hippocampus of depression model rats increases. The protein expression of CaMKII in the cortical and hippocampus of depression model rats increases.(5)The protein expression of p-ERK in the hippocampus of depression model rats decreases. Escitalopram?Metoprolol and N-acetylcysteine can increase the protein expression of p-ERK in the hippocampus of depression model rats.