Large dose of ketamine induces apoptosis in primary rat neuronal cultures

Objective To observe the effect of different doses of ketamine on rat neuronal injury during the period of rapid synaptogenesis. Methods Ketamine 0.01,0.1,1,and 2 mmol/L (K1,K2,K3,and K4 groups) or cell culture media (C group) was applied to primary rat neuronal cultures at development in vitro 6 d for 24 h. Twenty four hours after ketamine washout,neuron injury was measured by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) cell reduction assay,in situ terminal deoxynucleotidyl transferase (TdT)-mediated fluorescein-dUTP nick end labeling terminal (TUNEL) staining,cytosolic lactate dehydrogenase (LDH) release detection,and electron microscopic examination.Results Compared with C group,neurons in K3 or K4 group showed a decreased MTT value (P0.05) and increased percentage of TUNEL-positive cells (P0.05). Furthermore,electron micrographs showed more apoptotic neurons in K3 or K4 group. However,no significant difference was observed in the release of LDH in different groups.Conclusion Large dose of ketamine may induce apoptosis in primary rat neuronal cultures.