The study of cognitive function and synaptic plasticity in depressed rats following electroconvulsive shock / 中国神经精神疾病杂志

ABSTRACT

Objective To investigate the role of autophagy and synaptophysin (SYP) in cognitive impairment in de?pressed rats receiving electroconvulsive shock (ECS). Methods Clean and healthy adult male Sprague-Dawley rats were acclimatized to a standard laboratory environment for 7 days. The chronic unpredictable mild stress (CUMS) was used to establish the rat model of depression. Behavior tests were conducted before and after CUMS to evaluate the depression and cognition level of rats. After establishment of the model, 24 rats were randomly divided into ESC group (group E) and depression group (group D) with 12 rats in each group. The rats in group E were administered 80 mg/kg of propofol (10 mg/mL) by intraperitoneal injection, followed by ECS treatment. The rats in group D were administered propofol by intra?peritoneal injection, followed by sham-ECS treatments. The above interventions were conducted daily for 7 consecutive days. After the interventions, rats underwent behavior tests as before. Subsequently, rats were killed and specimens were collected for measurements. Immunohistochemistry was performed to examine autophagy markers such as Beclin 1 and LC3Ⅱand ELISA was used to detect SYP in the hippocampus. Results Group E after ECS significantly increased the percentage of sucrose preference (68.2%±8.7%), rearing times (7.0±1.9), total horizontal distance [(569.5±70.0) cm], es? cape latency [(21.9±5.3)s] and space exploration time [(20.5±3.9)s] compared with group D or group E before ECS. There was no significant difference in these index between groups before ECS or in group E between before and after ECS(P>0.05). Compared with group D, group E had upregulated protein expression levels of Beclin 1 and LC3Ⅱin CA1, CA3, DG as well as the area near the hippocampus and increased SYP contents (P<0.05). Conclusions Cognitive impairment in depression rats following ECS correlates with activated autophagy and increased SYP by ECS.