Metformin promotes angiogenesis and functional recovery in aged mice after spinal cord injury by adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway

Treatment with metformin can lead to the recovery of pleiotropic biological activities after spinal cord injury.However,its effect on spinal cord injury in aged mice remains unclear.Considering the essential role of angiogenesis during the regeneration process,we hypothesized that metformin activates the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway in endothelial cells,thereby promoting microvascular regeneration in aged mice after spinal cord injury.In this study,we established young and aged mouse models of contusive spinal cord injury using a modified Allen method.We found that aging hindered the recovery of neurological function and the formation of blood vessels in the spinal cord.Treatment with metformin promoted spinal cord microvascular endothelial cell migration and blood vessel formation in vitro.Furthermore,intraperitoneal injection of metformin in an in vivo model promoted endothelial cell proliferation and increased the density of new blood vessels in the spinal cord,thereby improving neurological function.The role of metformin was reversed by compound C,an adenosine monophosphate-activated protein kinase inhibitor,both in vivo and in vitro,suggesting that the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway likely regulates metformin-mediated angiogenesis after spinal cord injury.These findings suggest that metformin promotes vascular regeneration in the injured spinal cord by activating the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway,thereby improving the neurological function of aged mice after spinal cord injury.

Ramulus Cinnamomi extract attenuates neuroinflammatory responses via downregulating TLR4/MyD88 signaling pathway in BV2 cells

Ramulus Cinnamomi(RC), a traditional Chinese herb, has been used to attenuate inflammatory responses. The purpose of this study was to investigate the effect of RC extract on lipopolysaccharide(LPS)-induced neuroinflammation in BV2 microglial cells and the underlying mechanisms involved. BV2 cells were incubated with normal medium(control group), LPS, LPS plus 30 μg/m L RC extract, or LPS plus 100 μg/m L RC extract. The BV2 cell morphology was observed under an optical microscope and cell viability was detected by MTT assay. Nitric oxide level in BV2 cells was detected using Griess regents, and the levels of interleukin-6, interleukin-1β, and tumor necrosis factor α in BV2 cells were determined by ELISA. The expression levels of cyclooxygenase-2, Toll-like receptor 4 and myeloid differentiation factor 88 proteins were detected by western blot assay. Compared with the LPS group, both 30 and 100 μg/mL RC extract had no significant effect on the viability of BV2 cells. The levels of nitric oxide, interleukin-6, interleukin-1β and tumor necrosis factor α in BV2 cells were all significantly increased after LPS induction, and the levels were significantly reversed after treatment with 30 and 100 μg/mL RC extract. Furthermore, RC extract significantly inhibited the protein expression levels of cyclooxygenase-2, Toll-like receptor 4 and myeloid differentiation factor 88 in LPS-induced BV2 cells. Our findings suggest that RC extract alleviates neuroinflammation by downregulating the TLR4/My D88 signaling pathway.

The emerging role of nitric oxide in the synaptic dysfunction of vascular dementia

With an increase in global aging,the number of people affected by cerebrovascular diseases is also increasing,and the incidence of vascular dementia-closely related to cerebrovascular risk-is increasing at an epidemic rate.However,few therapeutic options exist that can markedly improve the cognitive impairment and prognosis of vascular dementia patients.Similarly in Alzheimer’s disease and other neurological disorders,synaptic dysfunction is recognized as the main reason for cognitive decline.Nitric oxide is one of the ubiquitous gaseous cellular messengers involved in multiple physiological and pathological processes of the central nervous system.Recently,nitric oxide has been implicated in regulating synaptic plasticity and plays an important role in the pathogenesis of vascular dementia.This review introduces in detail the emerging role of nitric oxide in physiological and pathological states of vascular dementia and summarizes the diverse effects of nitric oxide on different aspects of synaptic dysfunction,neuroinflammation,oxidative stress,and blood-brain barrier dysfunction that underlie the progress of vascular dementia.Additionally,we propose that targeting the nitric oxide-sGC-cGMP pathway using certain specific approaches may provide a novel therapeutic strategy for vascular dementia.

The Effect of YiQiFuMai on Ischemic Heart Failure by Improve Myocardial Microcirculation and Increase eNOS and VEGF Expression

Objective: To assess the effects of traditional Chinese medicine YiQiFuMai on cardiac function during the progression of ischemic heart failure. Methods: Rabbits were divided into sham, heart failure, and YiQiFuMai groups. The ischemic heart failure model was established in New Zealand white rabbits, which were intraperitoneally injected with YiQiFuMai injection and 0.9% sodium chloride after the operation. After six weeks, cardiac function was examined by ultrasound;serum BNP levels were measured by ELISA;p-AKT, eNOS, ICAM-1 and VEGF levels were evaluated by real-time PCR and Western-Blot;pathological changes of the myocardial tissue were observed by H&E staining;CD31 expression in tissue samples was analyzed by immunohistochemistry. The ultrastructure and microcirculation of myocardial tissue specimens from the three groups were assessed by transmission electron microscopy. Results: YiQiFuMai decreased serum BNP levels, and increased LVEF and reduced LVEDD at 6 weeks postoperatively. In addition, YiQiFuMai can improve myocardial damage and microcirculation structure, as assessed by histology and transmission electron microscope. At the molecular level, treatment with YiQiFuMai resulted in increased eNOS, VEGF and p-AKT levels but reduced ICAM-1 amounts compared with the heart failure group. Conclusion: Ischemic heart failure damages the microvascular structure and functions of the myocardium. Treatment with YiQiFuMai potentially ameliorates microcirculatory damage and alleviates cardiac failure by improving endothelial function and angiogenesis, and inhibiting inflammatory cell adhesion.

Differential effects of nitric oxide on rod and cone pathways in carp retina

The effects of nitric oxide (NO) on electroretinograms and light responses of horizontal cells intra-cellularly recorded from isolated, superfused carp retinas were studied. Sodium nitroprusside (SNP), an NO donor, suppressed scotopic b wave, while enhancing photopic b wave, and the effects could be blocked by hemoglobin, an NO chelator. Furthermore, following SNP application, light responses of rod horizontal cells were reduced in size and those of cone horizontal cells were increased. These results suggest that NO suppresses the activity of rod pathway, but enhances that of cone pathway in the outer retina. Moreover, the effects of methylene blue, an inhibitor of soluble guanylate cyclase, on rod and cone horizontal cells were just opposite to those of SNP, implying that the effects of NO may be mediated by cGMP.