Global Cerebral Ischemia in Male Long Evans Rats Impairs Dopaminergic/ΔFosB Signalling in the Mesocorticolimbic Pathway Without Altering Delay Discounting Rates

Global cerebral ischemia (GCI) in rats has been shown to promote exploration of anxiogenic zones of the Elevated-Plus Maze (EPM) and Open Field Test (OFT). This study investigated changes in impulsive choice and/or defensive responses as possible contributors of heightened anxiogenic exploration observed after ischemia. Impulsivity was assessed using delay discounting (DD) paradigms, while the Predator Odour Test (PO) served to assess changes in defensive responses towards a naturally aversive stimulus. Male Long Evans rats underwent 9 days of autoshaping training and 24 days of DD training prior to GCI or sham surgery (n = 9/group). Post-surgery, rats completed the OFT, EPM, and PO, followed by 6 days of DD sessions. Blood droplets served to evaluate corticosterone secretion associated with PO exposure. With impulsivity being regulated through mesocorticolimbic monoaminergic pathways, we also characterised post-ischemic changes in the expression of dopamine D2 receptors (DRD2), dopamine transporters (DAT), and 1FosB in the basolateral amygdala (BLA), nucleus accumbens core (NAcC) and shell (NAcS), and ventromedial prefrontal cortex (vmPFC) using immunohistofluorescence. Our findings revealed no impact of GCI on delay discounting rates, while PO approach behaviours were minimally affected. Nonetheless, GCI significantly reduced DRD2 and ΔFosB-ir in the NAcS and NAcC, respectively, while DAT-ir was diminished in both NAc subregions. Collectively, our findings refine the understanding of cognitive-behavioural and biochemical responses following stroke or cardiac arrest. They support significant alterations to the dopaminergic mesocorticolimbic pathway after ischemia, which are not associated with altered impulsive choice in a DD task but may influence locomotor exploration of the OFT and EPM.

Key Phytochemicals and Biological Functions of Chuanxiong Rhizoma Against Ischemic Stroke: A Network Pharmacology and Experimental Assessment

Presently, the treatment options for ischemic stroke (IS) are limited due to the complicated pathological process of the disease. Chuanxiong Rhizome (CR), also known as Conioselinum anthriscoides “Chuanxiong” (rhizome), is the most widely used traditional Chinese medicine for treating stroke. This study aimed to uncover the key phytochemicals and biological functions of CR against IS through a network pharmacology approach combining with IS pathophysiology analysis. We employed permanent unilateral common carotid artery ligation to construct a mouse model of global cerebral ischemia and found that cerebral ischemia injuries were improved after 7 days of gavage treatment of CR (1,300 mg/kg/day). CR exerts protective effects on neurons mainly by acting on targets related to synaptic structure, synaptic function, neuronal survival and neuronal growth. A total of 18 phytochemicals from CR based on UHPLC-MS/MS that corresponded to 85 anti-IS targets. Coniferyl ferulate, neocnidilide and ferulic acid were identified as the key phytochemicals of CR against IS. Its brain protective effects involve anti-inflammatory, anti-oxidative stress, and anti-cell death activities and improves blood circulation. Additionally, the two most important synergistic effects of CR phytochemicals in treating IS are prevention of infection and regulation of blood pressure. In brain samples of Sham mice, L-tryptophan and vanillin were detected, while L-tryptophan, gallic acid, vanillin and cryptochlorogenic acid were detected in IS mice by UHPLC–MS/MS. Our findings provide a pathophysiology relevant pharmacological basis for further researches on IS therapeutic drugs.

Evaluation of cerebroprotective effect of Ricinus communis leaves against ischemia reperfusion injury in rats

Background Ricinus communis (RC) has been used for a long time as natural origin medicine in the treatment of central nervous system ailments. This present study was designed to identify the possible role of Ricinus communis leaves extract against ischemia-reperfusion induced-neurobehavioral changes, oxidative stress, histopathological and cellular modifications in the brain. Methods Sprague Dawley (SD) rats (200–250 g) were induced to bilateral common carotid artery occlusion (BCCAO) for around 30 min later subjected to reperfusion for 24 h to induce cerebral injury by reperfusion. Ricinus communis leaves extract (250 and 500 mg/kg, p.o) was administered continuously for 14 days and on the 15th-day animals were subjected to ischemia-reperfusion injury. Different behavioral tests and biochemical parameters were assessed subsequently. Results Fourteen days Ricinus communis leaves extract (250 and 500 mg/kg, p.o.) treatment very significantly improved neurobehavioral alterations when compared to control ischemia-reperfusion. Ricinus communis leaves extract (250 and 500 mg/kg, p.o.) kg, i.p. treatment significantly attenuated oxidative damage when compared to ischemia-reperfusion (I/R) group animals. In addition, Ricinus communis leaves extract treatment was well supported histopathologically when compared to the ischemia-reperfusion (I/R) group. Conclusion The data from this study recommend that treatment with Ricinus communis leaves extract increases the antioxidant protection against BCCAO-induced global cerebral ischemia and demonstrates neuroprotective activity.

Urinary Proteome Changes in Global Cerebral Ischemia-Reperfusion Injury Rat Model Using Proteomics

Background Cerebral ischemia-reperfusion (I/R) injury is the leading cause of death in severe hypotension caused by cardiac arrest, drowning, and excessive blood loss. Urine can sensitively reflect pathophysiological changes in the brain even at an early stage. Methods In this study, a rat model of global cerebral I/R injury was established via Pulsinelli’s four-vessel occlusion (4-VO) method. The proteomics techniques of data-independent acquisition (DIA) and parallel reaction monitoring (PRM) were applied to profile the urinary proteome. The differentially expressed proteins were subjected to Gene Ontology (GO) and protein-protein interaction (PPI) analysis. Results One hundred and sixty-four proteins significantly differed in the 4-VO rat urine samples compared to the control samples (1.5-fold change, p<0.05). GO analysis showed that the acute-phase response, the ERK1 and ERK2 cascade, endopeptidase activity, blood coagulation, and angiogenesis were overrepresented. After PRM validation, fifteen differentially expressed proteins were identified, and their expression was consistent with the DIA quantification. The abundance of FGG, COMP, TFF2, and HG2A was significantly changed only at 12 h after I/R injury. APOE, FAIM3, FZD1, IL1R2, UROK and CD48 were upregulated only at 48 h after I/R injury. KNG1, CATZ, PTGDS, PRVA and HEPC showed an overall trend of upregulation or downregulation at 12 and 48 h after I/R injury, reflecting the progression of cerebral I/R injury. Conclusion In this study, fifteen differentially expressed urinary proteins were identified and validated in a 4-VO rat model. Eight of these proteins were reported to be associated with cerebral I/R injury. These findings provide important clues to inform the monitoring of cerebral I/R injury and further the current understanding of its molecular biological mechanisms.

Vanillin Attenuates Pro-Inflammatory Factors in tMCAO Mice Model Via Inhibiting of TLR4/NF-kB Signal Pathway

Purpose Vanillin has been reported to reduce hippocampal neuronal death in rats of global cerebral ischemia. However, the immunoregulatory mechanism of vanillin in ischemic mice is still unclear. Hence, this study aims to investigate the role of vanillin in transient middle cerebral artery occlusion (tMCAO) mice. Methods Transient cerebral ischemic stroke was induced by tMCAO surgery following by reperfusion in mice. After 24 hours of ischemia/reperfusion, Berderson scoring and TTC staining were used to evaluate neurological deficit and infarct volume, respectively. Furthermore, the expression of cytokines in ipsilateral hemisphere were detected by qPCR, ELISA and immunofluorescence. In vitro, LPS-stimulated primary and BV2 microglia cells were used to mimic neuroinflammation after ischemic stroke. Similarly, the expression of cytokines was detected by qPCR and ELISA. In addition, Western blotting was performed to evaluate the expression of Toll-like receptor 4 (TLR4), nuclear factor-κ-gene binding p65 (NF-κB p65) and phosphorylated NF-κB p65. Results Vanillin reduced infarct volume and improved motor function after ischemia/reperfusion. IL-1β and TNF-α were decreased in ischemic brain tissue of tMCAO mice after vanillin treatment. Similar changes were confirmed using the in vitro LPS-stimulated microglia cell model. Moreover, the decreasing expression of pro-inflammatory cytokines in vanillin group were related to TLR4/NF-κB signal pathway. Conclusions Taken together, vanillin decreased activation of microglia by inhibiting TLR4 /NF-κB signal pathway, and then reduced expression of pro-inflammatory cytokines IL-1β and TNF-α, which finally reduced infarct volume and improve motor function in tMCAO mice.