Morin Attenuated Cerebral Ischemia/Reperfusion Injury Through Promoting Angiogenesis Mediated by Angiopoietin-1-Tie-2 Axis and Wnt/ß-Catenin Pathway.

Cerebral damage following cerebral ischemia/reperfusion injury affects the neurological deficits and motor impairment of stroke patients in the long-term period. Angiogenesis, the essential process for restoration of cerebral blood flow (CBF) in the ischemic brain, promotes the recovery of neurological function following ischemia. The aim of this study was to investigate the long-term effects of morin on angiogenesis and functional outcomes in a middle cerebral artery occlusion (MCAO) and reperfusion model. Male Wistar rats were subjected to MCAO, and they were administered 30 mg/kg of morin at reperfusion via i.p. injection daily for 14 days. Fourteen days after I/R injury, the rats were evaluated for the brain damage, and angiogenic factors involved in Ang1/Tie-2 and Wnt/ß-catenin signaling. In addition, at 1, 7, and 14 days after reperfusion, rotarod and pole tests were performed to investigate the functional recovery. We found morin significantly reduced the infarct size, blood-brain barrier (BBB) leakage, and apoptotic cells at 14 days after I/R injury. It also promoted angiogenesis via boosting the expression of angiogenic proteins, such as angiopoietin 1 (Ang1), Tie-2, Wnt3α, ß-catenin, and cyclin D1. Morin-mediated angiogenesis was confirmed by a significant increase in microvessel's density in the penumbra area and an increase in von Willebrand factor (vWF) protein expression of the morin-treated rats. Moreover, the rotarod and pole tests also demonstrated morin increased functional recovery in the morin-treated rats compared to the vehicle rats. Therefore, our data exposed that morin promotes angiogenesis and improves functional outcomes in MCAO and reperfusion rats.

Agomelatine Exerts an Anti-inflammatory Effect by Inhibiting Microglial Activation Through TLR4/NLRP3 Pathway in pMCAO Rats.

Cerebral ischemic stroke is one of the main causes of death and long-term disability worldwide. However, the mechanism is unclear, and treatments are limited. In this study, we aimed to investigate the anti-inflammatory effect of agomelatine in a permanent middle cerebral artery occlusion (pMCAO) model. Forty-eight male Wistar rats were randomly divided into four groups: sham, pMCAO + vehicle, pMCAO + agomelatine (40 mg/kg, i.p.), and pMCAO + melatonin (10 mg/kg, i.p.) groups. On day 1 after permanent cerebral ischemia, the animals were sacrificed, and brain tissues were collected for western blot analysis, and immunohistochemistry. Agomelatine treatment ameliorated inflammatory responses by decreasing the protein levels of trigger Toll-like receptor (TLR4)/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway components together with nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome components. In addition, agomelatine suppressed microglial activation and pyroptotic cell death after cerebral ischemic injury. These results suggest that agomelatine exerts an anti-inflammatory effect and attenuates brain damage by inhibiting microglial activation through the TLR4/NLRP3 signaling pathway.

Morin protects the blood-brain barrier integrity against cerebral ischemia reperfusion through anti-inflammatory actions in rats.

This study aimed to investigate the effects of morin on cerebral damage and blood-brain barrier (BBB) integrity in a middle cerebral artery occlusion (MCAO) and reperfusion model. Wistar rats were exposed to MCAO for 2 h, followed by reperfusion. Thirty mg/kg of morin was administered via intraperitoneal injection at the different time points: before ischemia, during ischemia, and at reperfusion. The rats were divided into five groups, including sham, vehicle, and three groups of morin. Twenty-four hours after reperfusion, the rats were tested for neurological deficits, and the brains were harvested to assess brain damage. In addition, brains were harvested 72 h to determine BBB disruption. We found that morin significantly reduced reactive oxygen species production and lipid peroxidation. It also decreased inflammation via reducing the expression of Toll-like receptor 4, nuclear factor kappa-beta. Morin ameliorated cerebral damage and reduced apoptosis through decreasing the cerebral infarct size, including apoptotic cell death. Moreover, morin decreased the BBB damage via reducing Evans blue extravasation, neutrophil infiltration, and increasing tight junction protein expression. Therefore, morin protected against cerebral and BBB damage by attenuating oxidative stress, inflammation, and apoptosis in MCAO and reperfusion models.

Agomelatine protects against permanent cerebral ischaemia via the Nrf2-HO-1 pathway.

Stroke is a major cause of death and permanent disability worldwide. It has been reported that 85% of stroke patients undergo an ischaemic stroke. The standard treatment is currently recanalization. However, only 5% of patients have access to this treatment. Therefore, new strategies for permanent ischaemic stroke treatment need to be investigated. Agomelatine is a melatonergic agonist that acts on MT1/2 receptors and is an antagonist of 5-HT2c receptors, and melatonergic has pleiotropic effects, such as antioxidation or anti-inflammation effects. In this study, we focused on the effect of agomelatine on permanent cerebral ischaemia in a rat model. Male Wistar rats were randomly divided into the following four groups (n = 6/group): sham operating group, permanent ischaemic model group, permanent ischaemic model plus agomelatine (40 mg/kg, i.p) group and permanent ischaemic model plus melatonin (10 mg/kg, i.p) group. Twenty-four h after ischaemic onset, we investigated the neurological deficits and infarct volume using neurological deficit scores, 2,3,5-triphenyltetrazolium chloride (TTC) and transmission electron microscopy (Kochanski et al.). Moreover, we analysed Nrf2-HO-1 protein expression by Western blot. The results showed that agomelatine and melatonin decreased neuronal injury and promoted the Nrf2-HO-1 signalling pathway. These findings suggest that agomelatine and melatonin exert beneficial effects on permanent cerebral ischaemia.