scholarly journals Yi-Zhi-Fang-Dai Formula Exerts Neuroprotective Effects Against Pyroptosis and Blood–Brain Barrier–Glymphatic Dysfunctions to Prevent Amyloid-Beta Acute Accumulation After Cerebral Ischemia and Reperfusion in Rats

2021 ◽  
Vol 12 ◽  
Author(s):  
Zhongkuan Lyu ◽  
Qiyue Li ◽  
Zhonghai Yu ◽  
Yuanjin Chan ◽  
Lei Fu ◽  
...  

Background: The dysfunctional blood–brain barrier (BBB)–glymphatic system is responsible for triggering intracerebral amyloid-beta peptide (Aβ) accumulation and acts as the key link between ischemic stroke and dementia dominated by Alzheimer’s disease (AD). Recently, pyroptosis in cerebral ischemia and reperfusion (I/R) injury is demonstrated as a considerable mechanism causing BBB–glymphatic dysfunctions and Aβ acute accumulation in the brain. Targeting glial pyroptosis to protect BBB–glymphatic functions after cerebral I/R could offer a new viewpoint to prevent Aβ accumulation and poststroke dementia. Yi-Zhi-Fang-Dai formula (YZFDF) is an herbal prescription used to cure dementia with multiple effects of regulating inflammatory responses and protecting the BBB against toxic Aβ-induced damage. Hence, YZFDF potentially possesses neuroprotective effects against cerebral I/R injury and the early pathology of poststroke dementia, which evokes our current study.Objectives: The present study was designed to confirm the potential efficacy of YZFDF against cerebral I/R injury and explore the possible mechanism associated with alleviating Aβ acute accumulation.Methods: The models of cerebral I/R injury in rats were built by the method of middle cerebral artery occlusion/reperfusion (MCAO/R). First, neurological function assessment and cerebral infarct measurement were used for confirming the efficacy of YZFDF on cerebral I/R injury, and the optimal dosage (YZFDF-H) was selected to conduct the experiments, which included Western blotting detections of pyroptosis, Aβ1-42 oligomers, and NeuN, immunofluorescence observations of glial pyroptosis, aquaporin-4 (AQP-4), and Aβ locations, brain water content measurement, SMI 71 (a specific marker for BBB)/AQP-4 immunohistochemistry, and Nissl staining to further evaluate BBB–glymphatic functions and neuronal damage.Results: YZFDF obviously alleviated neurological deficits and cerebral infarct after cerebral I/R in rats. Furthermore, YZFDF could inactivate pyroptosis signaling via inhibiting caspase-1/11 activation and gasdermin D cleavage, ameliorate glial pyroptosis and neuroinflammation, protect against BBB collapse and AQP-4 depolarization, prevent Aβ acute accumulation and Aβ1-42 oligomers formation, and reduce neuronal damage and increase neurons survival after reperfusion.Conclusion: Our study indicated that YZFDF could exert neuroprotective effects on cerebral I/R injury and prevent Aβ acute accumulation in the brain after cerebral I/R associated with inhibiting neuroinflammation-related pyroptosis and BBB–glymphatic dysfunctions.

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Yong-Hua Tuo ◽  
Zhong Liu ◽  
Lei Feng ◽  
Zhong-Song Shi

Background: MicroRNA-29a (miR-29a) is involved in regulating cerebral ischemia process, but its underlying mechanism is unclear. We previously showed that inhibition of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX4) pathway improves the neurological outcome and increases the expression of miR-29a in transient middle cerebral artery occlusion (tMCAO) animal model. This study investigated the role of miR-29a in cerebral ischemia and reperfusion injury after mechanical reperfusion. Methods: The intraluminal filament tMCAO model was established in male rats with 2 hour ischemia followed by reperfusion. The expression of miR-29a and NOX4 in the infarction core and peri-infarct cortex were quantified at 0, 3, 12, and 24 hour after reperfusion. Permanent MCAO model was also evaluated after 2 hour and 24 hour ischemia. Intravenous miR-29a agomir was delivered immediately after reperfusion. Infarct volume, brain water content, neurological score, blood-brain barrier damage, and levels of miR-29a and NOX4 were determined at 24-hour after cerebral ischemia. Results: MiR-29a levels in the infarction core and peri-infarct cortex were significantly decreased at 3 hours after reperfusion in tMCAO group compared with the sham-operated group. The decreased levels of miR-29a lasted for 24 hours after cerebral ischemia. Dual-luciferase reporter system showed that NOX4 was the direct target gene of miR-29a. Intravenous miR-29a agomir increased the expression of miR-29a and suppressed NOX4 up-regulation in both the infarction core and peri-infarct cortex at 24-hour after ischemia compared with the tMCAO group (all p<0.05). Intravenous miR-29a agomir reduced infarct volume (24.7% ± 4.0% versus 37.8% ± 7.5%, p<0.01) at 24-hour after ischemia compared to the tMCAO group. MiR-29a agomir attenuated brain edema and reduced reperfusion-induced blood-brain barrier breakdown, resulting in improved neurological outcome (all p<0.05). Conclusions: MiR-29a overexpression protects against cerebral ischemia and reperfusion injury via downregulating NOX4. Infusion of miR-29a agomir immediately after reperfusion represents a novel adjunctive therapeutic strategy to improve outcome after mechanical reperfusion for acute ischemic stroke.


1953 ◽  
Vol 98 (5) ◽  
pp. 509-520 ◽  
Author(s):  
F. Stephen Vogel

Kernicteric pigment was extracted by means of chloroform from the brains of 3 infants. Solutions of it gave a positive diazo reaction, and, as determined electrophotometrically, gave maximum absorption of light having a wavelength of 425 mµ, being identical in these properties with chloroform solutions of crystalline mesobilirubin. Experimental kernicterus was regularly induced by injecting crystalline mesobilirubin intracerebrally in newborn kittens, the pigment staining the cerebral tissues a bright canary-yellow and being deposited abundantly in the nerve cells, as microscopic examinations showed, although these latter were otherwise intact. Bilirubin, likewise injected intracerebrally in newborn kittens, had no such effects. The possibility is discussed that the blood-brain barrier is altered in some infants with hyperbilirubinemia in such a way that bilirubin crosses it and is then reduced within the brain to mesobilirubin thus giving rise to the cerebral pigmentation of kernicterus. The fact that the pigment itself does not seem to damage the neurons, as the present studies show, makes it necessary to seek some other cause for the neuronal damage that is sometimes seen, in association with the pigmentation, in the naturally occurring disease.


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