Effects of dexmedetomidine on oxygen-glucose deprivation/reoxygenation damage in sevoflurane pre- and post-conditioned mouse neuroblastoma (NB2A) cell cultures

Objectives This study aims to evaluate the effects of dexmedetomidine (Dex) (0.1, 0.3, 0.5, 1.0,3.0, 10 µM) on cell viability (MTT), toxicity (NTT), apoptosis (Annexin V) and inflammation (IL-1β, IL-6, and TGF-β) in the neuroblastoma cell line of mouse origin (NB2a) exposed to sevoflurane (sevo) in a model of oxygen and glucose deprivation (OGD) injury. Methods The effects of Dex's different concentrations on cell viability and toxicity were analyzed with MTT and NTT. Control groups (C); Cells are incubated with DMEM normo-glucose (GN,positive control) and low-glucose (GL, negative control) medium for 4 hours in normoxic conditions. Group OGD+Sevo: Cells are incubated in the oxygen and glucose deprivation (OD+GL) medium for 3 hours in hypoxic condition which included gas mixtures of 5% CO2, 1% O2 and 92% N2 and 4%Sevo for 3 hours in a hypoxic chamber. Group PreDex: Before the OGD+Sevo procedure, cells are treated with Dex 3 and 10 µM for 4 hours. Group PostDex: After the OGD+Sevo procedure, cells were treated with Dex 3 and 10 µM for 4 hours. The inflammatory effects were assessed through immunohistochemistry using antibodies specific to IL1β, IL6, and TGF-β. Apoptotic effects of Dex were tested by the Annexin V. Data were analyzed through one-way ANOVA and Kruskal-Wallis. Data were given mean±SD. p<0.05 is statically significant. Results: Dexmedetomidine administered before hypoxic conditions increased cell viability at 0.5, 1, 3, and 10 µM concentrations in both low and normal-glucose medium in cells exposed to OD and 4%sevoflurane (p<0.01). Dexmedetomidine also increased cell viability after hypoxia, but only at 3 and 10 µM concentrations in normal-glucose medium and 0.5 µM concentration in low glucose medium. The apoptotic index was similar to control group in the pre-DEX group at 3 and 10 µM concentrations (p>0.05) Conclusions: Treatment with dexmedetomidine alone at increasing concentrations increased cell viability and proliferation in Nb2a cells. Dexmedetomidine at concentrations of 0.5, 1, 3, and 10 µM increased cell viability in cells exposed to OD/R and 4% sevoflurane in both low and normal glucose medium (p<0.01), but did not change the number of apoptotic cells. IL-1β decreased with increasing concentrations of dexmedetomidine. IL-6 was similar to the control group, while TGF-β significantly increased in a concentration-dependent manner with Dex. Treatment with Dex after the application of Sevo and OGY did not change cell viability and proliferation and increased the number of apoptotic cells.