Bilirubin oxidation end product B prevents CoCl2-induced primary cortical neuron apoptosis by promoting cell survival Akt/mTOR/p70S6K signaling pathway

Bilirubin oxidation end products (BOXes) are associated with the late-developing neurological deficits after subarachnoid hemorrhage (SAH) possibly by direct constricting the cerebral arteries, but their specific impacts on neurons especially in the state of hypoxia, a prominent feature during the late stage of SAH, remain unclear. Here, we explored the effects of BOXes on the primary cortical neurons subjected to CoCl2-induced hypoxia by evaluating the morphological and apoptotic changes of neurons. The present study showed that Z-BOX B but not Z-BOX A greatly alleviated CoCl2-induced neuronal cell deterioration and apoptosis. Immunocytochemical staining assay showed Z-BOX B significantly increased neurite length, the numbers of both secondary and tertiary branches, and the protein level of Synaptophysin. Caspase 3/7 apoptosis assay and DAPI staining showed that Z-BOX B markedly reduced primary cortical neurons apoptosis. The expression of cleaved Caspase-3 was suppressed by Z-BOX B treatment, while the expression of Bcl-xL was upregulated. To further discover the mechanism of the neuroprotective effect observed in Z-BOX B, we found Z-BOX B increased the expression of p-mTOR, pAkt, and p-p70S6K. In general, our results implicated Z-BOX B may prevent CoCl2-induced primary cortical neurons apoptosis by activating sAkt/mTOR/p70S6K signaling pathway. Hence, the present data may provide new insights into the pathophysiological mechanism of delayed neurological dysfunction after SAH and novel targets for treating SAH. (C) 2022 Elsevier Inc. All rights reserved.