Ex vivo models of retinal neurovascular diseases

Background:The ex vivo model represented by mouse retinal explants in culture is a useful experimental model to investigate the molecular mechanism involved in neurovascular diseases such as diabetic retinopathy(DR).It ensures an experimental overview with more complete respect to isolate cells and reduce problems in terms of accessibility and management with respect to in vivo model.In particular,it allows the evaluation of the relationship between retinal cells in response to the typical stressors involved in DR pathogenesis.Methods:Ex vivo retinal fragments derived from 3-to 5-week-old C57BL/6J mice.In particular,after dissection,the retina is cut into 4 separate fragments and transferred onto inserts placed with ganglion cells up.Once in culture,the explants could be treated in stress conditions typical of DR.In particular,this study protocol describes the procedure for the preparation and the culture of retinal explants with specific metabolic stressors such as high glucose(HG),advanced glycation end product(AGE),and oxidative stress(OS).In the end,this paper provides the protocols to perform molecular analyses in order to evaluate the response of retinal explants to stress and/or neuroprotective treatments.Discussion:The cultured retinal explants represent an ex vivo experimental model to investigate the molecular mechanisms involved in neurovascular diseases such as DR.Moreover,they could be useful to test the effect of neuroprotective compounds in response to metabolic stressors in a fewer time respect to an in vivo model.In conclusion,retinal explants in culture represent a valuable experimental model to conduct further studies to better understand the pathophysiology of DR.

Neuroprotective and neuroregenerative potential of pharmacologically-induced hypothermia with D-alanine D-leucine enkephalin in brain injury

Neurovascular disorders, such as traumatic brain injury and stroke, persist as leading causes of death and disability - thus, the search for novel therapeutic approaches for these disorders continues. Many hurdles have hindered the translation of effective therapies for traumatic brain injury and stroke primarily because of the inherent complexity of neuropathologies and an inability of current treatment approaches to adapt to the unique cell death pathways that accompany the disorder symptoms. Indeed, developing potent treatments for brain injury that incorporate dynamic and multiple disorder-engaging therapeutic targets are likely to produce more effective outcomes than traditional drugs. The therapeutic use of hypothermia presents a promising option which may fit these criteria. While regulated temperature reduction has displayed great promise in preclinical studies of brain injury, clinical trials have been far less consistent and associated with adverse effects, especially when hypothermia is pursued via systemic cooling. Accordingly, devising better methods of inducing hypothermia may facilitate the entry of this treatment modality into the clinic. The use of the delta opioid peptide D-alanine D-leucine enkephalin（DADLE） to pharmacologically induce temperature reduction may offer a potent alternative, as DADLE displays both the ability to cause temperature reduction and to confer a broad profile of other neuroprotective and neuroregenerative processes. This review explores the prospect of DADLE-mediated hypothermia to treat neurovascular brain injuries, emphasizing the translational steps necessary for its clinical translation.

Expression profiles of long noncoding RNAs in retinopathy of prematurity

Long noncoding RNA(lncRNA)regulates the proliferation and migration of human retinal endothelial cells,as well as retinal neovascularization in diabetic retinopathy.Based on similarities between the pathogenesis of retinopathy of prematurity(ROP)and diabetic retinopathy,lncRNA may also play a role in ROP.Seven-day-old mice were administered 75±2% oxygen for 5 days and normoxic air for another 5 days to establish a ROP model.Expression of lncRNA and mRNA in the retinal tissue of mice was detected by high-throughput sequencing technology,and biological functions of the resulted differentially expressed RNAs were evaluated by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses.The results showed that compared with the control group,57 lncRNAs were differentially expressed,including 43 upregulated and 14 downregulated,in the retinal tissue of ROP mice.Compared with control mice,42 mRNAs were differentially expressed in the retinal tissue of ROP mice,including 24 upregulated and 18 downregulated mRNAs.Differentially expressed genes were involved in ocular development and related metabolic pathways.The differentially expressed lncRNAs may regulate ROP in mice via microRNAs and multiple signaling pathways.Our results revealed that these differentially expressed lncRNAs may be therapeutic targets for ROP treatment.This study was approved by the Medical Ethics Committee of Shengjing Hospital of China Medical University on February 25,2016(approval No.2016PS074K).