Sevoflurane anesthesia during late gestation induces cognitive disorder in rat offspring via the TLR4/BDNF/TrkB/CREB pathway

Sevoflurane (Sevo) is widely used for general anesthesia during pregnancy. Emerging evidence indicates that maternal Sevo exposure can trigger developmental neurotoxicity in the offspring. Nonetheless, the underlying mechanisms need further investigation. Pregnant Sprague-Dawley rats on gestational day 18 were exposed to 3.5% Sevo to induce the rat model of neurotoxicity. TAK-242, a TLR4 Inhibitor, was administrated to inhibit the signaling transduction. Hippocampal tissues of rat offspring were harvested for immunohistochemical staining, TUNEL staining, Western blotting, ELISA, and measurement of oxidative stress-related markers. Serum samples were collected to evaluate lipid metabolism-associated factors. Morris water maze was implemented to test the cognitive function of offspring rats. Rat hippocampal neurons were isolated to elucidate the effect of TAK-242 on the BDNF/TrkB/CREB signaling in vitro. The results showed that maternal Sevo exposure during the third trimester induced neuroinflammation, lipid metabolism disturbance, and oxidative stress, and impaired the spatial learning and memory of rat offspring. Sevo upregulated TLR4 and impeded BDNF/TrkB/CREB signaling transduction in the hippocampus of rat offspring; TAK-242 administration reversed these effects. In conclusion, Sevo anesthesia during late gestation impairs the learning and memory ability of rat offspring possibly by promoting neuroinflammation and disturbing lipid metabolism via the TLR4/BDNF/TrkB/CREB pathway.

TLR4; cognitive impairment; inflammation; offspring; sevoflurane.