Ghrelin reduces cerebral ischemic injury in rats by reducing M1 microglia/macrophages

Mobilizing endogenous neuroprotection: the mechanism of the protective effect of acupuncture on the brain after stroke

Given its high morbidity, disability, and mortality rates, ischemic stroke (IS) is a severe disease posing a substantial public health threat. Although early thrombolytic therapy is effective in IS treatment, the limited time frame for its administration presents a formidable challenge. Upon occurrence, IS triggers an ischemic cascade response, inducing the brain to generate endogenous protective mechanisms against excitotoxicity and inflammation, among other pathological processes. Stroke patients often experience limited recovery stages. As a result, activating their innate self-protective capacity [endogenous brain protection (EBP)] is essential for neurological function recovery. Acupuncture has exhibited clinical efficacy in cerebral ischemic stroke (CIS) treatment by promoting the human body's self-preservation and "Zheng Qi" (a term in traditional Chinese medicine (TCM) describing positive capabilities such as self-immunity, self-recovery, and disease prevention). According to research, acupuncture can modulate astrocyte activity, decrease oxidative stress (OS), and protect neurons by inhibiting excitotoxicity, inflammation, and apoptosis via activating endogenous protective mechanisms within the brain. Furthermore, acupuncture was found to modulate microglia transformation, thereby reducing inflammation and autoimmune responses, as well as promoting blood flow restoration by regulating the vasculature or the blood-brain barrier (BBB). However, the precise mechanism underlying these processes remains unclear. Consequently, this review aims to shed light on the potential acupuncture-induced endogenous neuroprotective mechanisms by critically examining experimental evidence on the preventive and therapeutic effects exerted by acupuncture on CIS. This review offers a theoretical foundation for acupuncture-based stroke treatment.

Exploring Chinese herbal medicine for ischemic stroke: insights into microglia and signaling pathways

Ischemic stroke is a prevalent clinical condition affecting the central nervous system, characterized by a high mortality and disability rate. Its incidence is progressively rising, particularly among younger individuals, posing a significant threat to human well-being. The activation and polarization of microglia, leading to pro-inflammatory and anti-inflammatory responses, are widely recognized as pivotal factors in the pathogenesis of cerebral ischemia and reperfusion injury. Traditional Chinese herbal medicines (TCHMs) boasts a rich historical background, notable efficacy, and minimal adverse effects. It exerts its effects by modulating microglia activation and polarization, suppressing inflammatory responses, and ameliorating nerve injury through the mediation of microglia and various associated pathways (such as NF-κB signaling pathway, Toll-like signaling pathway, Notch signaling pathway, AMPK signaling pathway, MAPK signaling pathway, among others). Consequently, this article focuses on microglia as a therapeutic target, reviewing relevant pathway of literature on TCHMs to mitigate neuroinflammation and mediate IS injury, while also exploring research on drug delivery of TCHMs. The ultimate goal is to provide new insights that can contribute to the clinical management of IS using TCHMs.

The Interplay between Ghrelin and Microglia in Neuroinflammation: Implications for Obesity and Neurodegenerative Diseases

Numerous studies have shown that microglia are capable of producing a wide range of chemokines to promote inflammatory processes within the central nervous system (CNS). These cells share many phenotypical and functional characteristics with macrophages, suggesting that microglia participate in innate immune responses in the brain. Neuroinflammation induces neurometabolic alterations and increases in energy consumption. Microglia may constitute an important therapeutic target in neuroinflammation. Recent research has attempted to clarify the role of Ghre signaling in microglia on the regulation of energy balance, obesity, neuroinflammation and the occurrence of neurodegenerative diseases. These studies strongly suggest that Ghre modulates microglia activity and thus affects the pathophysiology of neurodegenerative diseases. This review aims to summarize what is known from the current literature on the way in which Ghre modulates microglial activity during neuroinflammation and their impact on neurometabolic alterations in neurodegenerative diseases. Understanding the role of Ghre in microglial activation/inhibition regulation could provide promising strategies for downregulating neuroinflammation and consequently for diminishing negative neurological outcomes.

Gualou Guizhi Decoction Improves Glucose Metabolism and Alleviates Microglia-Associated Inflammation after Cerebral Ischemia

Background

The classical prescription Gualou Guizhi decoction (GL), a mixture of Radix Trichosanthis, Ramulus Cinnamomi, Radix Paeoniae Alba, Radix Glycyrrhizae, Zingiberis Rhizoma Recens, and Fructus Ziziphus Jujuba, was clinically used in the treatment of limb spasms after stroke and has achieved remarkable therapeutic effects. However, the underlying mechanism still needs to be further explored.

Methods

Cerebral ischemia/reperfusion (CI/R) in Sprague-Dawley rats was induced by middle cerebral artery occlusion followed by filament removal. GL was intragastrically administered once daily for 7 or 14 consecutive days. The effect of GL on neurobehavioral impairment was evaluated. ¹⁸F-FDG micro-PET imaging was used to detect the effects of GL on glucose utilization in neural cells after CI/R. Immunohistochemical staining of glucose transporter 1 (Glut-1), glial fibrillary acidic protein (GFAP), and ionized calcium-binding adaptor molecule-1 (Iba-1) was further performed to show the effects of GL on cerebral glucose transport and the activation of inflammatory-related glial cells. Markers related to the microglial subtype were also assessed to investigate the effects of GL on microglia polarization.

Results

Neurological deficits induced by CI/R were significantly improved by GL administration. GL restored the glucose uptake in the ischemic hemisphere. Glut-1, the major glucose transporter in the brain, was significantly increased after GL treatment. Moreover, GL mitigated the activation of astrocytes and microglia after CI/R. Furthermore, GL significantly decreased proinflammatory M1-type microglial markers TNF-α and iNOS, while increasing anti-inflammatory M2 microglial markers CD206 and Arg-1.

Conclusion

GL enhanced the uptake and utilization of glucose in neural cells after CI/R. It exerted significant anti-inflammatory effects by regulating the polarization of microglia. These results provided further evidence supporting the clinical application of GL in the treatment of cerebral ischemic stroke.