Effect of Ginkgo biloba extract on TLR4/NF-κB pathway in alleviating cerebral ischemia in mice with acute cerebral ischemia / 中草药

ABSTRACT

Objective: To observe the effect of Ginkgo biloba extract on cerebral cortical ischemia in mice with acute cerebral ischemia and explore its effect on Toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) pathway. Methods: Sixty adult healthy male CD1 mice were randomly divided into sham operated group, model group, positive control group (3 × 104 IU/kg ulinastatin) and Ginkgo biloba extract low, medium and high doses (10, 20, 40 mg/kg) groups. The acute cerebral ischemia model in other five groups were all established except sham operated group. After successful modeling, mice in each group were given corresponding drugs iv tail, sham operation group and model group were given the same amount of saline. The pathological changes and histological grades of the cerebral cortex were observed. The survival neuron density of each group was compared. Malondialdehyde (MDA) and superoxide dismutase (SOD) were measured by colorimetry and xanthine oxidation respectively. The expressions of Toll like receptor 4 (TLR4) and nuclear transcription factor NF-κB p65 (NF-κB p65) mRNA were detected by real-time fluorescent quantitative PCR (qRT-PCR). Western blotting was used to detect TLR4 and NF-κB p65 protein expression. Results: In sham-operated group, the structure of cerebral cortex was normal, and the cells were full and arranged tightly and orderly. In the blank control group, the structure of cerebral cortex was severely damaged, and the cells were severely shrunk and disordered. Pathological changes in the Ulinastatin group and Ginkgo biloba extract groups were alleviated and dose-dependent. Compared with the sham operation group, the other five groups showed higher histological grade and MDA level in cerebral cortex (P < 0.05). Compared with the model group, the histological grade and MDA level of cerebral cortex decreased in ulinastatin group and Ginkgo biloba extract groups (P < 0.05). Compared with ulinastatin group, the histological grade and MDA content of brain cortex decreased in high dose group (P < 0.05). Compared with the sham operated group, the density of surviving neurons and the level of SOD in the other five groups decreased (P < 0.05). Compared with the model group, the density of survival neurons and the level of SOD in cortex increased in ulinastatin group and Ginkgo biloba extract group (P < 0.05). Compared with ulinastatin group, the density of survival neurons and the level of SOD in cortex increased in high dose group (P < 0.05). Compared with the sham operated group, the expression of TLR4, NF-κB p65 mRNA and protein in the other five groups increased (P < 0.05). Compared with the model group, the expression of TLR4, NF-κB p65 mRNA and protein in cortex of mice in ulinastatin group and Ginkgo biloba extract group decreased (P < 0.05). Compared with ulinastatin group, the expression of TLR4, NF-κB p65 mRNA and protein in the brain cortex of mice decreased in the high dose group (P < 0.05). Conclusion: Ginkgo biloba extract can alleviate the pathological changes caused by cerebral ischemia in mice with acute cerebral ischemia, alleviate neurological impairment, and improve oxidative stress indexes of cerebral cortex tissues. It is presumed that it may be achieved by regulating TLR4/NF-κB p65 signaling pathway and inhibiting the expressions of TLR4 and NF-κB p65 proteins.