Isoflurane decreases proliferation and differentiation, but none of the effects persist in human embryonic stem cell-derived neural progenitor cells

Abstract

Purpose

Volatile anesthetics are a potential risk for cognitive impairment in the developing brain. Isoflurane causes cell death, reduces neurogenesis, and changes neuronal differentiation. In this study, the effects of a single isoflurane exposure on the developing human brain were evaluated using human embryonic stem cell (hESC)-derived neural progenitor cells (NPCs).

Methods

Multipotent NPCs were derived from hESCs and randomly exposed to either 5 vol% isoflurane (4 h) or no isoflurane (control group). The cells were fixed after 1, 3, 5, and 7 days to evaluate differentiation using the ratio of β-III tubulin to nestin. Neuronal cell survival and proliferation were assessed using the WST-1 and bromodeoxyuridine (BrdU) cell proliferation assays, respectively. To evaluate the mechanism of isoflurane neurotoxicity, we added TAT-Pep5, a p75 neurotrophic receptor (p75^NTR) inhibitor, to each of the groups.

Results

Isoflurane had minimal or no effect on the cell survival of NPCs in vitro. Proliferation, assessed on the basis of BrdU incorporation, was inhibited in the isoflurane group on days 3 (p = 0.033) and 5 (p = 0.001). The ratios of β-III tubulin to nestin in the isoflurane group on days 1 and 3 were significantly lower (p = 0.004 and p = 0.029, respectively) than those in the control group. Anti-proliferative and differentiation-reducing effect did not persist. TAT-Pep5 pretreatment significantly blocked the isoflurane-mediated decrease in the β-III tubulin to nestin ratio (p = 0.012) on day 1.

Conclusion

Exposing NPCs to isoflurane hampered proliferation and differentiation but not neuronal survival. Isoflurane may be a powerful neuronal modulator during the early developmental period, partly mediated by activation of p75^NTR.

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