Ischemic stroke is a clinically common
cerebrovascular disease whose main risks include
necrosis, apoptosis and
cerebral infarction, all caused by
cerebral ischemia and reperfusion (I/R) injury. This process has particular significance for the treatment of
stroke patients. Notoginseng leaf
triterpenes (PNGL), as a valuable medicine, have been discovered to have
neuroprotective effects. However, it was not confirmed that whether PNGL may possess
neuroprotective effects against cerebral I/R injury. To explore the
neuroprotective effects of PNGL and their underlying mechanisms, a
middle cerebral artery occlusion/reperfusion (MCAO/R) model was established. In vivo results suggested that in MCAO/R model rats, PNGL pretreatment (73.0, 146, 292 mg/kg) remarkably decreased
infarct volume, reduced brain water content, and improved neurological functions; moreover, PNGL (73.0, 146, 292 mg/kg) significantly alleviated blood-brain barrier (BBB) disruption and inhibited neuronal apoptosis and neuronal loss caused by cerebral I/R injury, while PNGL with a different concertation (146, 292 mg/kg) significantly reduced the concentrations of
IL-6, TNF-α,
IL-1 β, and
HMGB1 in serums in a dose-dependent way, which indicated that
inflammation inhibition could be involved in the
neuroprotective effects of PNGL. The immunofluorescence and western blot analysis showed PNGL decreased
HMGB1 expression, suppressed the HMGB1-triggered
inflammation, and inhibited microglia activation (IBA1) in hippocampus and cortex, thus dose-dependently downregulating inflammatory
cytokines including
VCAM-1, MMP-9, MMP-2, and
ICAM-1 concentrations in ischemic brains. Interestingly, PNGL administration (146 mg/kg) significantly downregulated the levels of p-P44/42, p-JNK1/2 and p-P38 MAPK, and also inhibited expressions of the total NF-κB and phosphorylated NF-κB in ischemic brains, which was the downstream pathway triggered by
HMGB1. All of these results indicated that the protective effects of PNGL against cerebral I/R injury could be associated with inhibiting HMGB1-triggered
inflammation, suppressing the activation of MAPKs and NF-κB, and thus improved cerebral I/R-induced neuropathological changes. This study may offer insight into discovering new active compounds for the treatment of
ischemic stroke.