Plasma from healthy donors protects blood-brain barrier integrity via FGF21 and improves the recovery in a mouse model of cerebral ischaemia

Background Healthy plasma therapy reverses cognitive deficits and promotes neuroplasticity in ageing brain disease.However,whether healthy plasma therapy improve blood-brain barrier integrity after stroke remains unknown.Methods Here,we intravenously injected healthy female mouse plasma into adult female ischaemic stroke C57BL/6 mouse induced by 90 min transient middle cerebral artery occlusion for eight consecutive days.Infarct volume,brain atrophy and neurobehavioural tests were examined to assess the outcomes of plasma treatment.Cell apoptosis,blood-brain barrier integrity and fibroblast growth factor 21 knockout mice were used to explore the underlying mechanism.Results Plasma injection improved neurobehavioural recovery and decreased infarct volume,brain oedema and atrophy after stroke.Immunostaining showed that the number of transferase dUTP nick end labelling+/NeuN+cells decreased in the plasma-injected group.Meanwhile,plasma injection reduced ZO-1,occluding and claudin-5 tight junction gap formation and IgG extravasation at 3 days after ischaemic stroke.Western blot results showed that the FGF21 expression increased in the plasma-injected mice.However,using FGF21 knockout mouse plasma injecting to the ischaemic wild-type mice diminished the neuroprotective effects.Conclusions Our study demonstrated that healthy adult plasma treatment protected the structural and functional integrity of blood-brain barrier,reduced neuronal apoptosis and improved functional recovery via FGF21,opening a new avenue for ischaemic stroke therapy.

Hypoxia-controlled matrix metalloproteinase-9 hyperexpression promotes behavioral recovery after ischemia

Matrix metalloproteinase-9（MMP-9） plays a beneficial role in the sub-acute phase after ischemic stroke.However,unrestrained MMP-9 may disrupt the blood-brain barrier（BBB）,which has limited its use for the treatment of brain ischemia.In the present study,we constructed lentivirus mediated hypoxiacontrolled MMP-9 expression and explored its role after stroke.Hypoxia response element（HRE）was used to confine MMP-9 expression only to the hypoxic region of mouse brain after 120-min transient middle cerebral artery occlusion.Lentiviruses were injected into the peri-infarct area on day 7 after transient ischemia.We found hyperexpression of exogenous HRE-MMP-9 under the control of hypoxia,and its expression was mainly located in neurons and astrocytes without aggravation of BBB damage compared to the CMV group.Furthermore,mice in the HRE-MMP-9 group showed the best behavioral recovery compared with the normal saline,GFP,and SB-3CT groups.Therefore,hypoxia-controlled MMP-9 hyperexpression during the sub-acute phase of ischemia may provide a novel promising approach of gene therapy for stroke.

Overexpression of netrin-1 improves neurological outcomes in mice following transient middle cerebral artery occlusion

Netrin-1(NT-1)is one of the axon-guiding molecules that are critical for neuronal development.Because of its structural homology to the endothelial mitogens,NT-1 may have similar effects on vascular network formation.NT-1 was shown to be able to stimulate the proliferation and migration of human cerebral endothelial cells in vitro and also promote focal neovascularization in adult brain in vivo.In the present study,we reported the delivery of NT-1 using an adeno-associated virus(AAV)vector(AAV-NT-1)into mouse brain followed by transient middle cerebral artery occlusion(tMCAO).We found that AAV vectors did not elicit a detectable inflammatory response,cell loss or neuronal damage after brain transduction.The level of NT-1 was increased in the AAV-NT-1-transduced tMCAO mice compared with the control mice.Furthermore,the neurobehavioral outcomes were significantly improved in AAV-NT-1-transduced mice compared with the control animals(P<0.05)7 days after tMCAO.Our data suggests that NT-1 plays a neuronal function recovery role in ischemic brain and that NT-1 gene transfer might present a valuable approach to treat brain ischemic disorders.

Effect of ischaemic brain injury on sexual function in adult mice

Objective:Priapism refers to a condition with persistent abnormal erection of the penis,which is usually caused by disease or injury in the brain or spinal cord,or obstruction to the outflow of blood through the dorsal vein at the root of the penis,without sexual desires.The effect of cerebral ischaemia on sexual function is unknown.The aim of this study is to explore whether priapism occurs in adult mice.Furthermore,we examined the relationship between priapism and the region of infarct in the brain.Design:Adult male CD-1 mice who underwent permanent middle cerebral artery occlusion(pMCAO)were closely examined from 2 hours to 14 days postoperation.Results:We found that priapism occurs in∼80%of the mice with pMCAO,which could persist up to 14 days.Further study has demonstrated that the occurrence of priapism is related to the infarct region:priapism is found only in mice with ischaemic injury extending to the hypothalamus and the hippocampus regions.Conclusion:Our result suggested priapism may be used as a deep brain injury marker for evaluating brain injury in mice after pMCAO.