Phyllanthus emblica L. Regulates BDNF/PI3K Pathway to Modulate Glutathione for Mitoprotection and Neuroprotection in a Rodent Model of Ischemic Stroke.

INTRODUCTION: Ischemic stroke remains the leading cause of death worldwide and is the primary cause of disability globally. Numerous studies have shown that plant-origin medicines are promising and can influence the treatment of neurological disorders. Phyllanthus embilica L. (P. emblica or Amla) is one of the herbal plants whose medicinal properties are widely studied. The objective of the present study is to determine the neuroprotective effects of an aqueous extract of the fruit of P. emblica (hereinafter referred to as just P. emblica) on cerebral ischemia-reperfusion injury and explore if it can regulate BDNF/PI3K pathway to modulate glutathione for mitoprotection and neuroprotection. METHODS: In vivo studies were conducted on male Sprague Dawley rats, where rats were prophylactically administered 100 mg/kg P. emblica for 30 days. In the treatment group, rats were given 100 mg/kg P. emblica, 1 h post middle cerebral artery occlusion (MCAo). Rats were evaluated for neuro deficit and motor function tests. Brains were further harvested for infarct size evaluation, biochemical analysis, protein expression studies, and mitochondrial studies. RESULTS: Prophylaxis and treatment with P. emblica demonstrated significant improvement in functional outcome with a reduction in infarct size. Normalization of glutathione, nitrite, and malondialdehyde levels was also observed. Improvement in mitochondrial complex I and IV activities was also reported. Expressions of BDNF, PI3K, SDF1 and VEGF increased while that of ROCK2 decreased following P. emblica administration. CONCLUSION: P. emblica regulates BDNF/PI3K pathway to modulate glutathione in ischemic stroke to confer mitoprotection and neuroprotection.

Post-stroke Impairment of the Blood-Brain Barrier and Perifocal Vasogenic Edema Is Alleviated by Endovascular Mesenchymal Stem Cell Administration: Modulation of the PKCδ/MMP9/AQP4-Mediated Pathway.

Post-stroke edema and upregulation of aquaporin 4 (AQP4) water transport channels play a significant role in the progression of stroke pathology and deteriorating stroke outcomes. Prior studies from our lab have demonstrated the safety and efficacy of intra-arterial (IA) 1 × 105 mesenchymal stem cells (MSCs) administration post-stroke towards functional restoration and neuroprotection. Protein kinases have been reported to be involved in the signaling cascade of edema, with evidence supporting both its upregulation and downregulation at 24 h post-stroke. Among different protein kinase C (PKC) isoforms, the δ isoform is widely reported to play a pivotal role in the progression of ischemic reperfusion injury. Our present study aims to decipher the molecular mechanism of post-stroke IA MSCs mediated alleviation of perifocal vasogenic edema by PKCδ-mediated AQP4 regulation. Ovariectomized female SD rats were infused with 1 × 105 IA MSCs at 6 h post middle cerebral artery occlusion (MCAo). Animals were evaluated for behavioral and functional outcomes. Brains were harvested for evaluating infarct size and brain edema. Further, brain tissues were used for biochemical and molecular studies to decipher the possible molecular mechanism related to the regulation of PKCδ-mediated AQP4 expression. 1 × 105 IA MSCs at 6 h post-stroke confers neuroprotection as evident by the reduction in infarct size, edema, and improvement of functional outcome. An increase in GSH and catalase and a reduction in nitrite and MDA were observed along with a decrease in AQP4 and PKCδ expressions within the cortical brain regions of IA MSC-infused animals. The study gives preliminary evidence that IA MSCs administration post-stroke modulates PKCδ to regulate AQP4 expression which alleviates vasogenic edema towards neuroprotection. The study is novel and clinically relevant as no previous studies have looked into this aspect following IA delivery of stem cells in an animal model of ischemic stroke.