Effects of dalteparin on structure of hippocampal neurons of rats in chronic stress

Introduction: Stress is defined as any environmental change that disturbs the maintenance of brain homeostasis. Stress leads to production of pro-inflammatory cytokines that provoke neurodegenerative disorders. In the present study, we investigated the effects of dalteparin on hippocampal neuronal death induced by chronic stress in rats. Methods: the study was carried out on 60 adult male wistar rats, weighing 200- 250 gr. The rats were randomly divided into three groups: control, stress and stress + dalteparin (SD) groups. Animals in the stress and stress + dalteparin group were exposed to chronic stress for 4 weeks. Animals in the stress + dalteparin (SD) group received dalteparin (70,100 and 140 IU/kg/days i.p.) during the stress period. After the last stressor animals were sacrificed and concentration of IL-6 in serum was measured using ELISA. All animals were reperfused and their brains were processed for histological analysis through Nissl analysis. Results: We found that the serum concentration of IL-6 was significantly higher in the CMS (Chronic Mild Stress) exposure group than in the control group (p<0.05). Moreover, dalteparin, dose dependently decreased IL-6 concentration in the SD groups. Chronic stress also resulted in significant cell loss in hippocampal CA1, CA3 and hilus. Dalteparin markedly inhibited the decreases in number of hippocamoal CA1 and CA3 (p<0.01) and hilus (p<0.05) neurons caused by chronic stress. Discussion: chronic stress damages hippocampal CA1, CA3 and hilus neurons, and dalteparin protects hippocampus from damage induced by chronic stress.