Black bamboo root extract Quercetin protects against focal cerebral infarction in rats via TLR4 signaling pathway

Background: Black bamboo root is traditionally used in the treatment of neurological injuries with definite efficacy. The study aimed to investigate the efficacy, and mechanism of action of black bamboo root extract quercetin on inflammation, apoptosis, and oxidation in rats with focal cerebral infarction. Methods: We used 64 adult male Sprague-Dawley rats to replicate a focal cerebral infarction model using the wire bolus method. The treatment group underwent pharmacological intervention and the control group was injected with the Toll-like receptor 4 (TLR4) blocker TAK242. A focal cerebral infarction model was created using middle cerebral artery occlusion in Sprague-Dawley rats. The immunofluorescence double-labelling method was employed to ascertain the expression of Glial Fibrillary Acidic Protein (GFAP), Ionized calcium-binding adaptor molecule 1(Iba1) and TLR4 in glial cells. The expression of Neuron specific enolase (NSE) in neurons was determined through immunofluorescence. Immunohistochemistry was employed for the detection of cortical GFAP and Iba1 proteins. An immunoprotein blotting assay was employed to detect the presence of GFAP, Iba1, Nogo Receptor 3 (NgR3), Neurite outgrowth inhibitor-A (Nogo-A), Nuclear transcription factor NF-κB p65 (NF-κBp65) and TLR4. The concentration of Interleukin-17 (IL-17) was determined by enzyme-linked immunosorbent assay (ELISA). The activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) was measured by colorimetric assay, and the concentration of malondialdehyde (MDA) was determined by thiobarbituric acid assay (TBA). Results: The drug-treated group displayed a decrease in astrocyte GFAP and microglia iba1 with TLR4, neuronal NgR3 and Nogo-A expression; an increase in oxidase activity such as CAT, GSH-Px and SOD and a decrease in MDA expression. TLR4 receptor, NF-kB and IL-17 expression were decreased in control group after TLR4 inhibitor injection. Conclusion: Our findings suggest that black bamboo root extract has anti-inflammatory, and antioxidant effects in rats with cerebral ischaemia-reperfusion injury. The mechanism of action may involve the inhibition of TLR4 in astrocytes and microglia.