Dynamic Integrative Synaptic Plasticity Explains the Spacing Effect in the Transition from Short- to Long-Term Memory

Salvianolic acid A provides neuroprotective effects on cerebral ischemia-reperfusion injury in rats via PKA/CREB/c-Fos signaling pathway

BACKGROUND

Cerebral ischemia-reperfusion injury (CIRI) is a phenomenon that pathological injury of ischemic brain tissue is further aggravated after the restoration of blood supply. The complex pathological mechanism of CIRI has led to the failure of multiple neuroprotective agents in clinical studies. Salvianolic acid A (SAA) is a neuroprotective extract from Salvia miltiorrhiza Bge., with significant pharmacological activities in the treatment of brain injury. However, the neuroprotective mechanisms of SAA remain unclear.

PURPOSE

To explore the potential protective effect of SAA on CIRI and its mechanism, and to provide experimental basis for the research of new drugs for CIRI.

STUDY DESIGN

A model of transient middle cerebral artery occlusion (tMCAO) in rats was used to simulate clinical CIRI, and the neuroprotective effect of SAA on tMCAO rats was investigated within 14 days after reperfusion. The improvement effects of SAA on cognitive impairment of tMCAO rats were investigated by behavioral tests from days 7-14. Finally, the neuroprotective mechanism of SAA was investigated on day 14.

METHODS

The neuroprotective effects and mechanism of SAA were investigated by behavioral tests, HE and TUNEL staining, RNA sequence (RNA-seq) analysis and Western blot in tMCAO rats.

RESULTS

The brain protective effects of SAA were achieved by alleviating cerebral infarction, cerebral edema, cerebral atrophy and nerve injury in tMCAO rats. Meanwhile, SAA could effectively improve the cognitive impairment and pathological damage of hippocampal tissue, and inhibit cell apoptosis in tMCAO rats. Besides, SAA could provide neuroprotective effects by up-regulating the expression of Bcl-2, inhibiting the activation of Caspase 3, and regulating PKA/CREB/c-Fos signaling pathway.

CONCLUSION

SAA can significantly improve brain injury and cognitive impairment in CIRI rats, and this neuroprotective effect may be achieved through the anti-apoptotic effect and the regulation of PKA/CREB/c-Fos signaling pathway.

Fibroblast growth factor 2 contributes to the effect of salidroside on dendritic and synaptic plasticity after cerebral ischemia/reperfusion injury

Ischemic stroke, a serious neurological disease, is associated with cell death, axonal and dendritic plasticity, and other activities. Anti-inflammatory, anti-apoptotic, promote dendritic and synaptic plasticity are critical therapeutic targets after ischemic stroke. Fibroblast growth factor-2 (FGF2), which is involved in the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA)/CAMP response element (CRE)-binding protein (CREB) pathway, has been shown to facilitate dendritic and synaptic plasticity. Salidroside (Sal) has been reported to have anti-inflammatory, anti-oxidative, and anti-apoptotic effects; however, the underlying mechanisms of Sal in promoting dendritic and synaptic plasticity remain unclear. Here, the anti-inflammatory, anti-apoptotic, dendritic and synaptic plasticity effects of Sal were investigated in vitro in PC12 cells under oxygen-glucose deprivation/reoxygenation (OGD/R) conditions and in vivo in rats with middle cerebral artery occlusion/reperfusion (MCAO/R). We investigated the role of Sal in promoting dendritic and synaptic plasticity in the ischemic penumbra and whether the FGF2-mediated cAMP/PKA/CREB pathway was involved in this process. The present study demonstrated that Sal could significantly inhibit inflammation and apoptosis, and promote dendritic and synaptic plasticity. Overall, our study suggests that Sal is an effective treatment for ischemic stroke that functions via the FGF2-mediated cAMP/PKA/CREB pathway to promote dendritic and synaptic plasticity.