Total Saponins of Panax Notoginseng Modulate the Astrocyte Inflammatory Signaling Pathway and Attenuate Inflammatory Injury Induced by Oxygen- Glucose Deprivation/Reperfusion Injury in Rat Brain Microvascular Endothelial Cells

Reperfusion after cerebral ischemia causes brain injury. Total saponins of Panax notoginseng (PNS) have potential roles in protecting against cerebral ischemia-reperfusion injury. However, whether PNS regulates astrocytes on oxygen-glucose deprivation/reperfusion (OGD/R) injury in rat brain microvascular endothelial cells (BMECs) and its mechanism still need further clarification.Rat C6 glial cells were treated with PNS at different doses. Cell models were established by exposing C6 glial cells and BMECs to OGD/R. Cell viability was assessed, and levels of nitrite concentration, inflammatory factors (iNOS, IL-1β, IL-6, IL-8, TNF-α), and oxidative stress-related factors (MDA, SOD, GSH-Px, T-AOC) were subsequently measured through CCK8, Grice analysis, Western blot, and ELISA, respectively. The co-cultured C6 and endothelial cells were treated with PNS for 24 hours before model establishment. Then transendothelial electrical resistance (TEER), lactate dehydrogenase (LDH) activity, brain-derived neurotrophic factor (BDNF) content, and mRNA and protein levels and positive rates of tight junction proteins [Claudin-5, Occludin, ZO-1] were measured by a cell resistance meter, corresponding kits, ELISA, RT-qPCR, Western blot, and immunohistochemistry, respectively.PNS had no cytotoxicity. PNS reduced iNOS, IL-1β, IL-6, IL-8, and TNF-α levels in astrocytes, promoted T-AOC level and SOD and GSH-Px activities, and inhibited MDA levels, thus inhibiting oxidative stress in astrocytes. In addition, PNS alleviated OGD/R injury, reduced Na-Flu permeability, and enhanced TEER, LDH activity, BDNF content, and levels of tight junction proteins Claudin-5, Occludin, ZO-1 in the culture system of astrocytes and rat BMECs after OGD/R.PNS repressed astrocyte inflammation and attenuated OGD/R injury in rat BMECs.