Histochemistry of microinfarcts in the mouse brain after injection of fluorescent microspheres into the common carotid artery

The mouse model of multiple cerebral infarctions,established by injecting fluorescent microspheres into the common carotid artery,is a recent development in animal models of cerebral ischemia.To investigate its effectiveness,mouse models of cerebral infarction were created by injecting fluorescent microspheres,45–53μm in diameter,into the common carotid artery.Six hours after modeling,fluorescent microspheres were observed directly through a fluorescence stereomicroscope,both on the brain surface and in brain sections.Changes in blood vessels,neurons and glial cells associated with microinfarcts were examined using fluorescence histochemistry and immunohistochemistry.The microspheres were distributed mainly in the cerebral cortex,striatum and hippocampus ipsilateral to the side of injection.Microinfarcts were found in the brain regions where the fluorescent microspheres were present.Here the lodged microspheres induced vascular and neuronal injury and the activation of astroglia and microglia.These histopathological changes indicate that this animal model of multiple cerebral infarctions effectively simulates the changes of various cell types observed in multifocal microinfarcts.This model is an effective,additional tool to study the pathogenesis of ischemic stroke and could be used to evaluate therapeutic interventions.This study was approved by the Animal Ethics Committee of the Institute of Acupuncture and Moxibustion,China Academy of Chinese Medical Sciences(approval No.D2021-03-16-1)on March 16,2021.

Human bone marrow mesenchymal stem cell transplantation attenuates axonal injury in stroke rats

Previous studies have shown that transplantation of human bone marrow mesenchymal stem cells promotes neural functional recovery after stroke, but the neurorestorative mechanisms remain largely unknown. We hypothesized that functional recovery of myelinated axons may be one of underlying mechanisms. In this study, an ischemia/reperfusion rat model was established using the middle cerebral artery occlusion method. Rats were used to test the hypothesis that intravenous transplantation of human bone marrow mesenchyrnal stem cells through the femoral vein could exert neuroprotective effects against cerebral ischemia via a mechanism associated with the ability to attenuate axonal injury. The results of behavioral tests, infarction volume analysis and immunohistochemistry showed that cerebral ischemia caused severe damage to the myelin sheath and axons. After rats were intravenously transplanted with human bone marrow mesenchymal stem cells, the levels of axon and myelin sheath-related proteins, including microtubule-associated protein 2, myelin basic protein, and growth-associated protein 43, were elevated, infarct volume was decreased and neural function was improved in cerebral ischemic rats. These findings suggest that intravenously transplanted human bone marrow mesenchymal stem cells promote neural function. Possible mechanisms underlying these beneficial effects include resistance to demyelination after cerebral ischemia, prevention of axonal degeneration, and promotion of axonal regeneration.

Baicalin inhibits cell growth and induces autophagy via AMPK/ULK1 activation in MDA-MB-231 cells

OBJECTIVE To investigate the effects and molecular mechanisms of Baicalin,a natural flavonoid compound derived from Scutellariabaicalensis Georgi,in the triple-negative human breast cancer cell line MDAMB-231.METHODS Cel s(1.0×105mL-1)were seeded in96-well plates,6-well plates or 25 cm2flasks.After overnight incubation,various concentrations of Baicalin were added to cells for another 48 h.Cell viability was measured using XTT Assay.Cell growth and migration was measured using colony formation assay and wound healing assay,autophagy-related proteins were observed using Western blotting analysis.RESULTS A dose-dependent decrease in cell viability was induced by Baicalin(IC50=48.6μg·m L-1).The colony-forming activity of MDA-MB-231 cells was significantly reduced by various concentrations of baicalin(25,50,100μg·m L-1)(85.2±12.7%,41.3±12.3%,19.6±6.6%).Wound healing assay showed that the recovery rateof baicalin-treated groups(25,50,100μg·m L-1)were significantly lower than those of the untreated group(88.3±15.1%,52.1±15.5%,28.3±9.6%).Western blot showed that the AMP-activated protein kinase and ULK1 was clearly up-regulated and activated by Baicalin(25,50,100μg·m L-1)in a dose-dependent manner,and the expression level of autophagic marker Beclin-1 and LC3A/B was also unregulated by the same treatment.CONCLUSION The study revealed that baicalin interferes with breast cancer growth by inducing autophagy,which at least in part through AMPK/ULK1 activation.