Gentiopicroside Ameliorates Cerebrovascular Angiogenesis, Neuronal Injury and Immune Disorder in Rats with Cerebral Ischemia/Reperfusion Injury via VEGF and Phosphorylated Nrf2 Elevation

Abstract

Background: Cerebral ischemia-reperfusion (CI/R) injury is induction of blood flow restoration after an ischemic stroke. Gentiopicroside (GPC) is the principal active secoiridoid glycoside of Gentiana Manshurica Kitagawa. This research aimed to illuminate the function of GPC and its mechanism in CI/R injury.

Methods: After CI/R injury models were constructed, GPC (25, 50 or 100 mg/kg) was then administered by gavage to rats. Rats were grouped into Sham, CI/R, CI/R+25 mg/kg GPC, CI/R+50 mg/kg GPC, and CI/R+100 mg/kg GPC. Neuronal cells were exposed to oxygen-glucose deprivation and reperfusion (OGD/R) injury to establish ischemic-like conditions in vitro, and cells were further treated with 25, 50, or 100 μM GPC. Cells were grouped into control, OGD/R, OGD/R+25 μM GPC, OGD/R+50 μM GPC, and OGD/R+100 μM GPC. GPC's function on rat cerebral injury, angiogenesis, oxidative stress, neuronal injury and immune dysfunction in vivo was estimated using hematoxylin-eosin staining, Western blot, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining, commercial kits and enzyme linked-immunosorbent assay. Meanwhile, GPC's mechanism in CI/R injury was examined via Western blot. GPC's function in vitro was estimated via Cell Counting Kit-8 assay, 5-ethynyl-2'-deoxyuridine (EdU) staining, flow cytometry.

Results: GPC alleviated cerebral injury through decreasing cerebral infarction volume, cerebral indexes, brain water contents (p < 0.05). GPC reduced oxidative stress and boosted cerebral angiogenesis in CI/R rats (p < 0.05). Meanwhile, GPC weakened neuronal cell apoptosis, and decreased neuron-specific enolase and S100beta protein levels in CI/R rats. GPC reduced inflammatory cytokines contents in serum and brain tissues of CI/R rats (p < 0.05). Moreover, GPC increased the viability and proliferation in OGD/R-treated neuronal cells, but decreased cell apoptosis (p < 0.05). Mechanistically, GPC upregulated vascular endothelial growth factor (VEGF) and phosphorylated nuclear factor E2-related factor 2 (p-Nrf2) levels in CI/R rat brain tissues (p < 0.05).

Conclusions: GPC reduced cerebrovascular angiogenesis, neuronal injury and immune disorder in CI/R injury through elevating VEGF and p-Nrf2.

Keywords: cerebral ischemia-reperfusion injury; cerebrovascular angiogenesis; gentiopicroside; neuronal injury, immune disorder.