Refined Qingkailing protects the in vitro neurovascular unit against oxygen–glucose deprivation and re-oxygenation-induced injury

Since the proposal of the neurovascular unit (NVU) theory, it has become almost mandatory for neuroprotective medicines against ischaemic stroke (IS) to focus on this unit. Refined Qingkailing (RQKL) is a compound composed of hyodeoxycholic acid, geniposide, baicalin and cholic acid, which has shown great potential in the treatment of IS, but its effect on NVU has not been fully studied. The purpose of this study was to investigate the potential biological pathways that underlie the protective effects of RQKL against NVU damage induced by oxygen-glucose deprivation and re-oxygenation (OGD/R). Using in vitro OGD/R models, we looked into whether RQKL protects the NVU. In order to create an in vitro NVU that resembles IS, we created an OGD/R injury model using primary cultures of brain microvascular endothelial cells, neurons, and astrocytes. Based on our results, we present evidence, for the first time, that RQKL treatment of the injury caused by OGD/R significantly (1) kept the blood brain barrier (BBB) functioning and maintained the architecture of the neurons, (2) mitigated the oxidative stress damage, inflammatory cytokine release, and neuronal death, and (3) upregulated the expression of neurotrophic factors generated from glial cells and the brain in the in vitro model. Therefore, RQKL has a variety of preventive effects against NVU damage caused by OGD/R. RQKL may be a suitable medication for treating IS in a clinical setting.