Low-temperature 3D-printed collagen/chitosan scaffolds loaded with exosomes derived from neural stem cells pretreated with insulin growth factor-1 enhance neural regeneration after traumatic brain injury

There are various clinical treatments for traumatic brain injury,including surgery,drug therapy,and rehabilitation therapy;howeve r,the therapeutic effects are limited.Scaffolds combined with exosomes represent a promising but challenging method for improving the repair of traumatic brain injury.In this study,we determined the ability of a novel 3D-printed collagen/chitosan scaffold loaded with exosomes derived from neural stem cells pretreated with insulin-like growth factor-1(3D-CC-INEXOS) to improve traumatic brain injury repair and functional recove ry after traumatic brain injury in rats.Composite scaffolds comprising collagen,chitosan,and exosomes derived from neural stem cells pretreated with insulin-like growth fa ctor-1(INEXOS) continuously released exosomes for 2weeks.Transplantation of 3D-CC-INExos scaffolds significantly improved motor and cognitive functions in a rat traumatic brain injury model,as assessed by the Morris water maze test and modified neurological seve rity scores.In addition,immunofluorescence staining and transmission electron microscopy showed that3D-CC-INExos implantation significantly improved the recove ry of damaged nerve tissue in the injured area.In conclusion,this study suggests that transplanted3D-CC-INExos scaffolds might provide a potential strategy for the treatment of traumatic brain injury and lay a solid foundation for clinical translation.

Early brainstem hemorrhage progression:multi-sequence magnetic resonance imaging and histopathology

According to clinical statistics,the mortality of patients with early brainstem hemorrhage is high.In this study,we established rat models of brainstem hemorrhage by injecting type Ⅶ collagenase into the right basotegmental pontine and investigated the pathological changes of early brainstem hemorrhage using multi-sequence magnetic resonance imaging and histopathological methods.We found that brainstem hematoma gradually formed in the injured rats over the first 3 days and then reduced after 7 days.The edema that occurred was mainly of the vasogenic type.No complete myelin sheath structure was found around the focus of the brainstem hemorrhage.The integrity and continuity of nerve fibers gradually deteriorated over the first 7 days.Neuronal degeneration was mild in the first 3 days and then obviously aggravated on the 7^(th)day.Inflammatory cytokines,interleukin-1β,and tumor necrosis factorαappeared on the 1st day after intracerebral hemorrhage,reached peak levels on the 3^(rd)day,and decreased from the 7^(th)day.Our findings show the characteristics of the progression of early brainstem hemorrhage.

吴茱萸碱调节SDF-1α/CXCR4信号通路对颅内动脉瘤血管平滑肌细胞增殖和凋亡的影响

目的探究吴茱萸碱通过调节基质细胞衍生因子1α(SDF-1α)/CXC趋化因子受体4(CXCR4)信号通路对颅内动脉瘤(IA)血管平滑肌细胞(VSMCs)的增殖和凋亡的作用。方法24只小鼠随机分为对照组和IA组,每组12只。IA组通过定位手术注射弹性蛋白酶制造IA模型小鼠,然后通过HE染色观察动脉组织变化。随后将小鼠主动脉血管平滑肌细胞(MOVAS)先用MTT法检测吴茱萸碱浓度对细胞的活性影响,然后将MOVAS分为ctrl组、Model组(H_(2)O_(2)诱导损伤组)、低浓度吴茱萸碱组(0.50μmol/L)、高浓度吴茱萸碱组(1.00μmol/L)、高浓度吴茱萸碱+CTCE-0214组(1.00μmol/L吴茱萸碱+10 mg/kg SDF-1α/CXCR4激活剂)。CCK-8试剂盒检测细胞活性;流式细胞术检测细胞凋亡;Western blot检测SDF-1α、CXCR4、BAX、增殖细胞核抗原(PCNA)、平滑肌22α(SM22α)和平滑肌α肌动蛋白(α-SMA)的蛋白表达。结果与对照组正常动脉组织比较,IA组的IA组织出现明显的病理变化,损伤严重。在MOVAS细胞实验中,与ctrl组比较,Model组的细胞凋亡率、SDF-1α、CXCR4、BAX蛋白表达增加,而细胞存活率、PCNA、SM22α、α-SMA含量降低(P<0.05)。与Model组比较,低浓度吴茱萸碱组、高浓度吴茱萸碱组的细胞凋亡率、SDF-1α、CXCR4、BAX蛋白表达降低,而细胞存活率、PCNA、SM22α、α-SMA含量升高(P<0.05);与高浓度吴茱萸碱组比较,高浓度吴茱萸碱+CTCE-0214组细胞凋亡率、SDF-1α、CXCR4、BAX蛋白表达升高,而细胞存活率、PCNA、SM22α、α-SMA含量降低(P<0.05)。结论吴茱萸碱可能通过抑制SDF-1α/CXCR4信号通路进而抑制颅内动脉瘤血管平滑肌细胞的凋亡,促进其增殖。

紫草素调节HIF-1α/NLRP3信号通路对蛛网膜下腔出血大鼠神经功能损伤的影响

目的探究紫草素调节缺氧诱导因子-1α(HIF-1α)/NOD样受体热蛋白结构域相关蛋白3(NLRP3)信号通路对蛛网膜下腔出血(SAH)大鼠神经功能损伤的影响。方法大鼠随机分为假手术组、模型组、YC-1(HIF-1α抑制剂,5 mg/kg)组、紫草素低剂量组(4 mg/kg)、紫草素高剂量组(25 mg/kg)、紫草素高剂量(25 mg/kg)+AG1(HIF-1α激活剂,10 mg/kg)组,每组15只。采用颈内动脉刺破法制备SAH模型。采用Zea-Longa评分法评估6组大鼠神经功能;ELISA法检测血清肿瘤坏死因子α(TNF-α)、白介素-6(IL-6)和IL-1β水平;HE染色观察大鼠海马组织形态学变化,TUNEL染色法检测海马神经元凋亡率;伊文思蓝染色检测血脑屏障通透性;商品化试剂盒检测大鼠脑组织超氧化物歧化酶(SOD)、过氧化氢酶(MDA)、丙二醛(CAT)水平,Western blot检测大鼠脑组织Bax、Bcl-2、HIF-1α、NLRP3蛋白表达。结果假手术组大鼠海马神经元形态结构正常;与假手术组相比,模型组大鼠海马神经元有大量水肿、结构模糊,有细胞核溶解,变型固缩,部分细胞核消失,大鼠神经功能评分、血清TNF-α、IL-6和IL-1β水平、海马神经元凋亡率、伊文思蓝渗出量、脑组织MDA水平、Bax、HIF-1α、NLRP3水平显著增加,脑组织SOD、CAT水平、Bcl-2蛋白水平显著降低(P<0.05);与模型组比较,紫草素低剂量组、紫草素高剂量组和YC-1组鼠海马神经元病理损伤显著改善,大鼠神经功能评分、血清TNF-α、IL-6和IL-1β水平、海马神经元凋亡率、伊文思蓝渗出量、脑组织MDA水平、Bax、HIF-1α、NLRP3水平显著降低,SOD、CAT水平、Bcl-2蛋白水平显著升高(P<0.05);与紫草素高剂量组比较,紫草素高剂量+AG1组大鼠海马神经元病理损伤显著加重,大鼠神经功能评分、血清TNF-α、IL-6和IL-1β水平、海马神经元凋亡率、伊文思蓝渗出量、脑组织MDA水平、Bax、HIF-1α、NLRP3水平显著增加,SOD、CAT水平、Bcl-2蛋白水平显著降低(P<0.05)。结论紫草素抑制HIF-1α/NLRP3信号通路以降低氧化应激和炎性反应,进而改善SAH大鼠神经功能损伤。

伴和不伴快速眼动睡眠行为障碍帕金森病患者自发脑活动的静息态功能磁共振成像研究

目的快速眼动睡眠行为障碍(rapid eye movement sleep behavior disorder,RBD)是帕金森病(Parkinson's disease,PD)常见的非运动症状且是重要预后因素。本研究通过静息态功能磁共振成像,利用度中心度(degreecentrality,DC)和低频振幅(amplitudes of low-frequency fluctuation,ALFF)分析PD伴RBD和不伴有RBD患者组以及健康对照组三组间DC值和ALFF值,探索PD伴RBD患者脑功能活动特征及RBD特异性脑区,探究RBD发生的病理机制。材料与方法招募20例伴有RBD的PD患者(PD-RBD组)、40例无RBD的PD患者(PD-nonRBD组)和44例年龄性别匹配的健康对照(健康对照组),三组被试均接受磁共振扫描。利用静息态数据计算DC值和ALFF值,探测脑功能特征。结果方差分析结果显示三组间DC值主效应脑区为右侧中央前回、颞上回、小脑、额中回(P<0.05,FDR校正);ALFF值主效应脑区为左侧海马旁回、楔叶、舌回(P<0.05,FDR校正)。进一步分析发现相比于PD-nonRBD组,PD-RBD患者表现为右侧额中回DC值升高(t=4.02;P=0.007,FDR校正);左侧楔前叶DC值降低(t=5.30;P=0.009,FDR校正)。相比于健康对照组,PD-RBD患者表现为左侧额上回、小脑、右侧颞上回、左侧颞中回、额中回的DC值升高(P<0.05,FDR校正);左侧中央前回、颞上回和颞中回的DC值降低(P<0.05,FDR校正);右侧楔叶ALFF值降低(P<0.05,FDR校正)。结论PD-RBD在DC和ALFF上有独特的影像学特征,特别是右侧额中回、左侧楔前叶的功能异常可能与PD患者RBD的发生密切相关。

Lactate metabolism in neurodegenerative diseases

Lactate,a byproduct of glycolysis,was thought to be a metabolic waste until the discovery of the Warburg effect.Lactate not only functions as a metabolic substrate to provide energy but can also function as a signaling molecule to modulate cellular functions under pathophysiological conditions.The Astrocyte-Neuron Lactate Shuttle has cla rified that lactate plays a pivotal role in the central nervous system.Moreover,protein lactylation highlights the novel role of lactate in regulating transcription,cellular functions,and disease development.This review summarizes the recent advances in lactate metabolism and its role in neurodegenerative diseases,thus providing optimal pers pectives for future research.

不同管饲方法对脑卒中后吞咽障碍患者营养状况、吞咽功能及并发症的影响

目的:探讨间歇口-胃管管饲法(IOE)和持续鼻-胃管管饲法(NGT)对脑卒中后吞咽障碍患者营养状况、吞咽功能及并发症的影响。方法:按照治疗方法不同将120例脑卒中后吞咽障碍患者分为IOE组和NGT组,每组各60例。两组采取相应管饲法,均连续干预14 d。比较两组营养状况[体质量指数(BMI)、血红蛋白(Hb)、白蛋白(ALB)、总蛋白(TP)]、吞咽功能[功能性经口摄食量表(FOIS)]、管饲舒适度及并发症发生情况。结果:干预后,IOE组BMI、Hb、ALB、TP水平及FOIS评分均高于NGT组(P<0.05)。IOE组鼻腔不适、口腔干燥、吞咽不适发生率均低于NGT组(P<0.05)。IOE组并发症总发生率低于NGT组(8.33%vs.26.67%,P<0.05)。结论:相比于NGT,IOE可以更好地改善对脑卒中后吞咽障碍患者营养状况、吞咽功能,且IOE的管饲舒适度更高、并发症发生率更低。

运动耐力层级化康复护理在脑梗死介入术后患者中的应用效果

目的 探究运动耐力层级化康复护理在脑梗死介入术后患者中的应用效果。方法 选取2021年4月至2022年5月江苏省南通市第六人民医院脑科中心收治的100例脑梗死介入术后患者作为研究对象,根据随机数字表法将其分为对照组和干预组,各50例。对照组实施常规康复护理措施,干预组实施运动耐力层级化康复护理措施。于入院1 d、干预3个月后,对两组康复锻炼依从性、运动功能、并发症等进行比较分析。结果 干预3个月后,两组康复锻炼依从性评分高于入院1 d,且干预组高于对照组(P<0.05)。两组肢体功能评分高于入院1 d,且干预组高于对照组(P<0.05)。干预组压力性损伤、下肢深静脉血栓、感染、偏瘫等并发症总发生率低于对照组(P<0.05)。结论 对脑梗死介入术后患者采取运动耐力层级化康复护理措施,有利于提升患者康复锻炼依从性,改善机体运动功能,降低并发症。

基于潜变量混合增长模型预测颅内动脉瘤手术患者治疗依从性的影响因素

目的基于潜变量混合增长模型(LGMM)分析颅内动脉瘤(IA)手术患者治疗依从性的影响因素。方法选取接受IA手术的150例患者为研究对象。收集患者一般资料,采用治疗依从性量表评估患者依从性。应用LGMM预测IA术后患者治疗依从性的变化轨迹,并通过多因素Logistic回归分析法分析IA患者治疗依从性的影响因素。结果本研究共回收有效问卷138份,有效问卷回收率为92.00%。IA术后患者治疗依从性得分为(5.18±1.59)分。经LGMM拟合后,选取3个潜在剖面。依从性好的患者为37例(26.81%),依从性中等的患者为42例(30.43%),依从性差的患者为59例(42.75%)。依从性好患者的潜在剖面类别归属概率矩阵为97.29%,依从性中等患者为95.24%,依从性差患者为98.31%。依从性差患者中年龄为30~50岁、初中及以下文化水平、合并2种及以上疾病、自费(医疗费用)和Hunt-Hess分级为Ⅲ级者占比高于依从性好患者和依从性中等患者,差异有统计学意义(P<0.05)。年龄30~50岁、Hunt-Hess分级为Ⅲ级、合并2种及以上疾病、文化程度为初中及以下、自费(医疗费用)是治疗依从性的影响因素(P<0.05)。结论IA手术患者治疗依从性较低,且存在异质性。年龄为30~50岁、初中及以下文化水平、合并2种及以上疾病、医疗费用支付方式为自费以及Hunt-Hess分级为Ⅲ级均为IA手术患者依从性的影响因素。

高压氧联合人工心肺复苏对呼吸心跳骤停患者心脑缺血性损伤的影响

目的探讨高压氧联合人工心肺复苏(Cardiopulmonary Resuscitation,CPR)对呼吸心跳骤停患者心脑缺血性损伤的影响。方法回顾性分析2021年3月—2023年6月期间上海天佑医院收治的60例呼吸心跳骤停患者的临床资料,根据救治方法分为对照组和观察组,其中单纯应用人工CPR治疗的30例患者为对照组,增用高压氧治疗的30例患者为观察组。比较两组患者的CPR治疗相关情况、格拉斯哥昏迷量表(Glasgow Coma Scale,GCS)评分、振幅整合脑电图(Amplitude Integrated Electroencephalogram,aEEG)评分、血压、动脉血氧分压(Arterial Partial Pressure of Oxygen,PaO_(2))、血氧饱和度(Oxygen Saturation,SaO_(2))、血乳酸水平。结果治疗后,观察组患者的GCS评分、aEEG评分依次为(9.31±0.66)分、(4.35±0.56)分,高于对照组的(8.85±0.62)分、(3.98±0.67)分,差异有统计学意义(t=2.782、2.321,P均<0.05)。观察组患者的PaO_(2)、SaO_(2)水平高于对照组,血乳酸水平低于对照组,差异有统计学意义(P均<0.05)。结论在呼吸心跳骤停患者应用人工CPR过程中,增用高压氧能够影响患者的GCS评分、aEEG评分,促进PaO_(2)、SaO_(2)指标的升高,并可降低血乳酸水平,对心脑缺血性损伤具有一定的改善作用。

The interaction between KIF21A and KANK1 regulates dendritic morphology and synapse plasticity in neurons

Morphological alterations in dendritic spines have been linked to changes in functional communication between neurons that affect learning and memory.Kinesin-4 KIF21A helps organize the microtubule-actin network at the cell cortex by interacting with KANK1;however,whether KIF21A modulates dendritic structure and function in neurons remains unknown.In this study,we found that KIF21A was distributed in a subset of dendritic spines,and that these KIF21A-positive spines were larger and more structurally plastic than KIF21A-negative spines.Furthermore,the interaction between KIF21A and KANK1 was found to be critical for dendritic spine morphogenesis and synaptic plasticity.Knockdown of either KIF21A or KANK1 inhibited dendritic spine morphogenesis and dendritic branching,and these deficits were fully rescued by coexpressing full-length KIF21A or KANK1,but not by proteins with mutations disrupting direct binding between KIF21A and KANK1 or binding between KANK1 and talin1.Knocking down KIF21A in the hippocampus of rats inhibited the amplitudes of long-term potentiation induced by high-frequency stimulation and negatively impacted the animals’cognitive abilities.Taken together,our findings demonstrate the function of KIF21A in modulating spine morphology and provide insight into its role in synaptic function.

Brain stem cells as the cell of origin in glioma

Glioma incidence rates in the United States are near 20000 new cases per year, with a median survival time of 14.6 mo for high-grade gliomas due to limited therapeutic options. The origins of these tumors and their many subtypes remain a matter of investigation. Evidence from mouse models of glioma and human clinical data have provided clues about the cell types and initiating oncogenic mutations that drive gliomagenesis, a topic we review here. There has been mixed evidence as to whether or not the cells of origin are neural stem cells, progenitor cells or differentiated progeny. Many of the existing murine models target cell populations defined by lineage-specific promoters or employ lineagetracing methods to track the potential cells of origin. Our ability to target specific cell populations will likely increase concurrently with the knowledge gleaned from an understanding of neurogenesis in the adult brain. The cell of origin is one variable in tumorigenesis, as oncogenes or tumor suppressor genes may differentially transform the neuroglial cell types. Knowledge of key driver mutations and susceptible cell types will allow us to understand cancer biology from a developmental standpoint and enable early interventional strategies and biomarker discovery.

Simultaneous determination of LY3214996,abemaciclib,and M2 and M20 metabolites in human plasma,cerebrospinal fluid,and brain tumor by LC-MS/MS

A sensitive and rapid liquid chromatography tandem mass spectrometry(LC-MS/MS)method was established for the quantification of total and unbound concentrations of LY3214996,an extracellular signal-regulated kinase inhibitor;abemaciclib,a cyclin-dependent kinase 4/6 inhibitor;and abemaciclib active metabolites,M2 and M20,in human plasma,brain tumor,and cerebrospinal fluid samples.The method was validated over a concentration range of 0.2e500 nM within a total run time of 3.8 min using isocratic elution on a Kinetex^(TM) F_(5) column.Detection was performed on a Sciex QTRAP 6500t mass spectrometer employing multiple reaction monitoring mode under positive electrospray ionization.The intra-and inter-batch accuracy as well as the precision of the method for all matrices was within ±20% and ≤20% at the lower limit of quantification,and within ±15% and ≤15% for other quality control levels for all analytes.The unbound fractions of drugs and metabolites in spiked and patient samples were determined using an optimized equilibrium dialysis.The validated method was successfully applied in a phase 0/2 clinical trial to assess the central nervous system penetration of LY3214996 and abemaciclib.

Lack of Efficacy of Bevacizumab Plus Irinotecan in Children with Recurrent Malignant Glioma and Diffuse Brainstem Glioma:A Pediatric Brain Tumor Consortium Study

PURPOSE:A phase Ⅱ study of bevacizumab(BVZ) plus irinotecan(CPT-11) was conducted in children with recurrent malignant glioma(MG) and intrinsic brainstem glioma(BSG).PATIENTS AND METHODS:Eligible patients received two doses of BVZ

帕金森病合并脑微出血患者的认知和运动功能差异及其影响因素分析

目的探讨帕金森病合并脑微出血患者的认知及运动功能差异及其影响因素。方法选择2016年2月至2019年6月宁波大学医学院附属医院收治的原发性帕金森病患者256例为研究对象。根据患者是否合并脑微出血分为非脑微出血组(214例)及脑微出血组(42例)。所有患者均采用简易智力状态检查量表(MMSE)评估认知功能,以统一帕金森病评定量表Ⅲ(UPDRSⅢ)、Hoehn&Yahr分期评估其运动功能,Logistic回归方法分析认知功能的影响因素。分析脑微出血与认知功能和运动功能的关系。结果脑微出血组MMSE评分定向力、注意力和计算力、语言能力项得分及总分低于非脑微出血组(均P<0.01),认知功能障碍(轻、中、重度)比例高于非脑微出血组[83.3%(35/42)比55.6%(119/214)](P<0.05)。脑微出血组帕金森病患者UPDRSⅢ评分震颤、肌强直、运动迟缓、轴性运动症状项得分及总分均高于非脑微出血组(均P<0.01),中、重度运动障碍比例高于非脑微出血组[57.1%(24/42)比37.4%(80/214)](P<0.05)。二元Logistic回归分析结果显示,侧脑室周围白质病变及深部白质病变Fazekas评分和UPDRS Ⅲ评分为帕金森病患者认知和运动功能的影响因素(均P<0.05)。排除年龄、高血压等混杂因素后,脑微出血与MMSE评分呈显著负相关(r=-0.245,P<0.001),与UPDRSⅢ评分呈显著正相关(r=0.308,P<0.001)。结论帕金森病并发脑微出血患者认知功能及运动功能均较差,且其脑白质损害程度更严重,Fazekas和UPDRSⅢ评分是以上差异的影响因素。

Development and distribution of PAG-immunoreactive neurons in the central pathway of trigeminal proprioception of the rat brainstem*

Objective: To investigate the development and distribution of phosphate-activated glutaminase like immunoreactive (PAG-LI) neurons in the central pathway of trigeminal proprioception of the rat brainstem. Methods: The immunohistochemitry techniques were used. Results: (1) At embryonic day 17 (E17), PAG-LI neurons were initially observed in the mesencephalic trigeminal nucleus (Vme). All PAG-LI neurons were large round neurons with moderate immunostaining. The immunoreactivity grew intense and attained adult-like pattern at P10. (2) Not until postnatal day 10 (P10) did a few PAG-LI neurons appear in the area ven-tral to the motor trigeminal nucleus (AVM) and area dorsal to the superior olivery nucleus (ADO), and not until P12 in the dorsomedial part of the subnucleus oralis of the spinal trigeminal nucleus (Vodm) and dorso-medial part of the principal sensory trigeminal nucleus (Vpdm). As development proceeded, more and more neurons in them were immunostained, and some PAG-LI neurons were detected in the lateral reticular forma-tion adjacent to the Vodm(LRF)and the caudolateral part of the supratrigeminal nucleus (Vsup-CL) at P21. Conclusion: In the central pathway of trigeminal proprioception of the rat brainstem, PAG-LI neurons ap-peared during two stages: The first stage from E17 to P10, PAG-LI neurons appeared in the Vme and reached adult-like pattern; the second stage from P10 to P21, PAG-LI neurons appeared in the Vodm, LRF, Vpdm, Vsup-CL, ADO, AVM and gradually reached adult-like pattern. This might be relative to the estab-lishment of jaw movement patterns.

EFFECTS OF SEVERE HEMORRHAGE ON IN VIVO BRAIN AND SMALL INTESTINE MITOCHONDRIAL NADH AND MICROCIRCULATORY BLOOD FLOW

Severe body stress induced by hypoxemia and hypotension may lead to total body energy state deterioration.The perfusion of the most vital organs is maintained at the expense of“less vital”organs.In the present study,we used a multi-site multiparametric(MSMP)monitoring system for real-time evaluation of tissue blood flow(TBF)and mitochondrial NADH fluorescence of the brain and the small intestine following hemorrhage.In Group 1,uncontrolled hemorrhage,mean arterial pressure(MAP)was decreased to 40mmHg within 2 minutes and shed blood was re-infused after 30minutes.In Group 2,controlled hemorrhage,during the 30minutes of hemorrhage,MAP was kept at 40mmHg.During hemorrhage,in both groups,the intestinal TBF and NADH deteriorated,while the brain remained relatively well protected.In Group 1,all parameters partly recovered within the hemorrhage phase,while in Group 2,complete recovery occurred only after resuscitation.At the end of the experiment,both models showed a decrease in intestinal viability(TBF decreased,NADH increased),while the brain metabolic state in Group 2 declined slightly.Our unique multi-parametric monitoring device demonstrated that,under hemorrhage,the small intestine responded entirely differently from the brain.This may suggest the potential usefulness of the monitoring of less vital organs,as proxy organs,in critical conditions such as massive hemorrhage.The present study also highlights the importance of mitochondrial function monitoring in similar conditions in the clinical environment.

HYPERBARIC HYPEROXIA AND THE BRAIN IN VIVO:THE BALANCE BETWEEN THERAPY AND TOXICITY

Hyperbaric oxygenation(HBO)treatment protocols utilize low pressures up to 3ATA.Higher pressures may induce side effects such as convulsions due to brain toxicity.The optimal HBO pressure allowing for maximal therapy and minimal toxicity is under controversy.However,it can be evaluated by monitoring oxygen delivery,saturation,and consumption.In this study,the monitoring system fixed on the rats’brain cortex included a time-sharing fluorometer-reflectometer for monitoring mitochondrial NADH and hemoglobin oxygenation(HbO_(2))combined with Laser Doppler Flowmetry(LDF)for blood-flow monitoring.Rats were located in a hyperbaric chamber and exposed to different pressures.The HBO pressure caused an increase in HbO_(2)and a decrease in NADH in proportion to the increase in hyperbaric pressure,up to a nearly maximum effect at 2.5ATA.At 6ATA,15 minutes before convulsions started,blood volume and NADH started to increase,while tissue O_(2)supply by hemoglobin remained stable.Oxygen pool includes oxygen dissolved in the plasma and also bounded to hemoglobin.Above 2.5ATA,hemoglobin is fully saturated and the oxygen pool nourishment derives only from the oxygen dissolved in the plasma,exceeding the physiological ability for autoregulation;hence,homeostasis is disturbed and convulsions appear.This information is vital because pressures around 2.5ATA–3ATA are standard clinically applied pressures used to treat most of the pathophysiological problems considering the potential benefit which must be balanced against the potential toxicity.This study enables,for the first time,to evaluate the oxygenation level of hemoglobin in the microcirculation.Furthermore,our study showed that additional oxygen pressure(above 2.5ATA)caused brain oxygen toxicity within a short variable period of time after the pressure elevation.

HOW DOES ANESTHESIA AFFECT VARIOUS LEVELS OF EXPERIMENTAL TRAUMATIC BRAIN INJURY?

The use of anesthetics is a well-known treatment for severely injured patients.In the present study we tested the pathophysiology of several levels of injury damage in a rat model and also tested the effect of Equithesin on brain vitality in these models.Traumatic Brain Injury(TBI)was induced using thefluid percussion injury model in four levels:mild,moderate and two levels of severe TBI.Brain real-time evaluation was performed by the multiparametric monitoring assembly(MPA)which enable cerebral bloodflow(CBF)monitoring by laser Dopplerflowmetry,mitochondrial NADH(Nicotinamide adenine dinucleotide)monitoring by thefluorometric technique,ionic homehostasis using special mini-electrodes,intracranial pressure(ICP)by the ICP camino device and needle electrodes for ECoG(Electrocorticogram)recording.Our results showed high correlation between the level of impact and the extent of changes in the physiological properties of the injury as indicated by the changes in all parameters monitored using the MPA device.Moreover,Equithesin improved CBF,ionic extracellular level and mitochondrial redox state following mild and moderate TBI while in severe TBI,Equithesin did not improve the metabolic state of the cerebral cortex,although it decreased the mortality rate from 66%to 20%,and following extra-severe TBI level,Equithesin did not improve survival rate.In conclusion it seems that Equithesin's protective effect exists under mild to moderate levels of injury and not in case of severe injuries.