OBJECTIVE  To investigate the effect of Elaphurus davidiauus Cornu (EDC) on anti-depressive effect via chronic unexpected mild stress (CUMS) model and to locate EDC efficient substances with the effect of inhibiting the oxidative damage induced neuronal apoptosis.

  METHODS  EDC extracts were prepared, and the anti-depression effect of EDC extracts was evaluated by sucrose preference test, tail suspension test and forced swimming test in CUMS mice model. The expression of malondialdehyde (MDA) and the activities of catalase (CAT), superoxide dismutase (SOD) and glutathione reductase (GSH) in the serum of mice were determined by related detection kits. The mouse hippocampal neuronal cell line (HT22) and rat adrenal pheochromocytoma cells (PC12) were used to construct an oxidative injury model with hydrogen peroxide. The protective effect of EDC on the oxidative injury was evaluated by MTT assay. TUNEL staining was used to investigate the anti-apoptosis effect of a water extract from EDC (EDC-WE) on HT22 cells after oxidative damage. The expression of neuronal apoptosis pathway-related proteins, such as Caspase3, Cleaved-caspase3, Caspase9 and Cleaved-caspase9 were detected by Western blotting. The EDC-WE was further separated into four fractions with molecular weight more than 100 kD, molecular weight 30~100 kD, molecular weight 10~30 kD and molecular weight less than 10 kD by ultrafiltration. The protective effect of different molecular weight segments of EDC-WE on oxidative damage in HT22 cells was evaluated by the MTT method. The effect of the anti-apoptosis effect on components with molecular weight less than 10 kD was analyzed by TUNEL staining and its mechanism of anti-apoptosis via detecting the Caspase signaling pathway by Western blot.

  RESULTS  EDC extracts could significantly up-regulate the sucrose preference rate of model mice, shorten the immobile time of tail suspension and forced swimming test, and EDC-WE showed the strongest effect among the three extracts. EDC-WE could prevent the hydrogen peroxide oxidative damage induced HT22 cell apoptosis via regulating the Caspase signaling pathway. The water-soluble substance of EDC with molecular weight less than 10 kD had the strongest effect on protecting against cell oxidative damage among the four components.

  CONCLUSION  The anti-depressive effect of EDC-WE is related to its effect on inhibiting the oxidation induced apoptosis of neuronal cells via regulating the Caspase signaling pathway, and the water-soluble substance of EDC with molecular weight less than 10 kD may be the key effective component responsible for the anti-depressive effect.