Effects of Anesthesia Neurotoxicity on Oligodendrocyte Development and Myelination: An In Vitro Study Using Primary Cultures

General anesthesia allows safe and comfortable performance of surgical operations, but early-life general anesthetic (GA) exposure may cause harm to the developing brain. The mechanism for this phenomenon remains unclear. Laboratory models demonstrate a variety of effects of GA on the immature brain, but consequences of early-life anesthetic exposure on oligodendrocyte development have seldomly been reported. To better understand the potentially toxic effects of GA on brain development, this study uses oligodendrocyte progenitor cells (OPCs) from primary cultures to investigate the effects of isoflurane (ISO), a canonical inhaled GA, on oligodendrocyte development and myelination. OPCs from cerebral cortices of newborn mice (P3) were cultured and purified with the anti-O4 microbeads technique. More than 92% of cells were confirmed as OPCs. On day of in vitro (DIV) 4, OPCs were exposed to 1.5% ISO in carrier gas (5% CO2 and 95% air) for 4h, or to carrier gas only as a control (CON). Immunocytochemistry (ICC) was conducted to evaluate the alteration of OPC development. By DIV 8, compared to CON group, the number of apoptotic OPCs in ISO exposure increased and the number of proliferating OPCs decreased. By DIV 12, the ratio of mature oligodendrocytes to OPCs was reduced, which indicated that oligodendrocyte differentiation was impaired. By DIV 14, the area of oligodendrocyte processes, which represents oligodendrocyte maturation, was smaller in ISO than CON. In OPC/neuron co-cultures, ISO exposure reduced the sum length of oligodendrocyte processes wrapping the neuronal axon. In conclusion, early GA exposure substantially disrupts oligodendrocyte development and myelination, which probably contributes to cognitive disorders.