Effects of ginkgobalide B on neurocyte apoptosis and the expression of protein kinase B after experimental hypoxic-ischemic brain injury / 中华物理医学与康复杂志

ABSTRACT

Objective To observe the effect of ginkgobalide B (GB) on neurocyte apoptosis and protein kinase B expression in neonatal rats after hypoxic-ischemic brain damage (HIBD).Methods Ninety seven-day-old Sprague-Dawley rats were randomly divided into a sham group,an HIBD group and a GB group,each of 30.HIBD was induced in the HIBD and GB groups using the classical Rice method,while the sham group was given a sham operation.GB (10 mg/kg) was injected intraperitoneally to the rats in the GB group at 0 h and 24 h after the modeling.Then 6 rats were killed 6 h,12 h,24 h and 48 h after the modeling,and the expression of caspase-3 mRNA was detected using a real-time PCR to find the time point of maximum effectiveness.Then to further explore the role of the PI3K-AKT pathway in the anti-apoptosis effect of ginkgolide B,a a GB+LY294002 group of 6 rats,which was injected with PI3K-AKT pathway inhibitor LY294002 (1.8 mg/kg) intraperitoneally at 30 min before the modeling and with GB(10 mg/kg) at 0 h and 24 h after the modeling,was added to the experiment.Hematoxylin-eosin staining,terminal-deoxynucleotidyl transferase-mediated nick end labeling and immunohistochemical staining were then used to observe any morphological changes in the cortex,to detect neuronal apoptosis and to quantify the expression of P-AKT protein.Results The expression of caspase-3 in the HI and GB groups began to increase 6 hours after the HIBD and reached a peak after 24 hours,followed by a gradual decline.The expression of caspase-3 in the GB group was significantly lower than in the HI group throughout,while that of both of those groups was significantly higher than in the sham group.Apoptosis-positive cells and the expression of caspase-3increased had significantly in the HI,GB and GB+LY294002 groups 24 hours after the HIBD compared with the sham group,while the expression of P-AKT protein had decreased significantly.Moreover,the apoptosis-positive cells and the expression of caspase-3 of the HI and GB+LY294002 groups were significantly high-er than those of the GB group,while their expression of P-AKT protein was significantly lower after 24 hours.Conclusion Ginkgobalide B can decrease neurocyte apoptosis caused by hypoxic-ischemic brain damage,especially at 24 h after the damage.The PI3K-AKT signaling pathway plays an important role in this effect.