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Published on: June 26, 2020
Neurovascular and neuronal protection by E64d after focal cerebral ischemia in rats
Tamiji Tsubokawa1, Mitsuo Yamaguchi-Okada, John W Calvert
1Department of Physiology and Pharmacology, Loma Linda University School of Medicine, California 92354, USA.
Abstract:
Calpains and cathepsins are two families of proteases that play an important role in ischemic cell death. In this study, we investigated the effect of E64d, a mu-calpain and cathepsin B inhibitor, in the prevention of neuronal and endothelial apoptotic cell death after focal cerebral ischemia in rats. Rats underwent 2 hr of transient focal ischemia from middle cerebral artery occlusion (MCAO) and were sacrificed 24 hr later. E64d (5 mg/ kg intraperitoneally) was administered 30 min before MCAO. Assessment included neurological function, infarction volume, brain water content, blood-brain barrier permeability, histology, and immunohistochemistry. The E64d-treated rats had significant brain protection against ischemic damage. We observed a reduction of infarction volume, brain edema, and improved neurological scores in E64d-treated rats compared with the nontreated control. Furthermore, there was a remarkable reduction in both proteases and caspase-3 activation and apoptotic changes in both neurons and endothelial cells in E64d-treated rats. These results suggest that E64d protects the brain against ischemic/reperfusion injury by attenuating neuronal and endothelial apoptosis.
Insights
The protease inhibitor E64d significantly protected rat brains from stroke damage by reducing neuronal and endothelial cell apoptosis. This neuroprotective effect was observed after middle cerebral artery occlusion (MCAO) and improved neurological function.
Area of Science:
- Neuroscience
- Biochemistry
- Pharmacology
Background:
- Proteases, including calpains and cathepsins, are implicated in ischemic cell death.
- Neuronal and endothelial apoptosis contribute to brain damage following focal cerebral ischemia.
Purpose of the Study:
- To investigate the neuroprotective effects of E64d, a dual inhibitor of mu-calpain and cathepsin B, against ischemic injury.
- To assess the impact of E64d on neuronal and endothelial apoptotic cell death in a rat model of focal cerebral ischemia.
Main Methods:
- Rats underwent 2 hours of transient focal cerebral ischemia induced by middle cerebral artery occlusion (MCAO).
- E64d was administered intraperitoneally 30 minutes before MCAO.
- Evaluated outcomes included neurological function, infarct volume, brain edema, blood-brain barrier permeability, histology, and immunohistochemistry.
Main Results:
- E64d treatment significantly reduced infarct volume, brain edema, and improved neurological scores compared to controls.
- A notable decrease in protease activity and caspase-3 activation was observed in E64d-treated rats.
- Apoptotic changes in both neurons and endothelial cells were markedly reduced following E64d administration.
Conclusions:
- E64d demonstrates significant neuroprotective effects against ischemic/reperfusion injury in rats.
- Inhibition of calpains and cathepsins by E64d attenuates neuronal and endothelial apoptosis, contributing to brain protection.
- E64d holds potential as a therapeutic agent for mitigating stroke-related brain damage.
