Evaluation of Novel Rapid Analytical Methods to Categorize Extra Virgin Olive Oil Based on the Coulometrically Determined Antioxidant Capacity and on the Spectrophotometric Assessment of Phenolic Compounds.

The lack of a practical "fit for the purpose" analytical protocol is the main limitation that has hampered the exploitation of the EFSA analytical health claim on the extra virgin olive oil (EVOO) biophenols, more than ten years since its introduction. In this work, two analytical methods recently developed in our laboratories for categorizing EVOO have been evaluated on a set of 16 samples from Cilento (Campania Region, southern Italy) and compared to other commonly used quality indexes. The Coulometrically Determined Antioxidant Capacity (CDAC) is associated with the component responsible for the health-promoting properties and oxidative stability of EVOO. The Fast Blue BB (FBBB) assay consists of the spectrophotometric (420 nm) determination of biophenols-FBBB diazonium coupling products generated in unfractionated EVOO. The FBBB assay and HPLC-UV reference method provide values highly correlated to each other. Fourteen of sixteen EVOO samples with CDAC > 10 mmol kg-1 and FBBB absorbance > 0.5 had HPLC-determined biophenols > 250 mg kg-1, and therefore eligible for the EFSA health claim. Consistently, two EVOO samples with HPLC-determined biophenols < 250 mg kg-1 had CDAC values and FBBB absorbance below the respective thresholds. CDAC and FBBB assays are proposed individually or in combination as methods to categorize EVOO samples in alternative to HPLC-UV.

Rapid and cost-efficient microplate assay for the accurate quantification of total phenolics in seaweeds.

Brown seaweeds (Phaeophyceae) are a rich source of polyphenols (up to 20% dry weight) with a structure based on phloroglucinol (1,3,5-trihydroxybenzene). To-date the determination of total phenolics content (TPC) involves a redox reaction with the Folin-Ciocalteu (FC) reagent. However, side reactions with other reducing substances preclude accurate, direct measurement of TPC. This research reports a novel microplate assay involving a coupling reaction between phloroglucinol with Fast Blue BB (FBBB) diazonium salt, at basic pH, to form a stable tri-azo complex with maximum absorbance at 450 nm. Linear regression correlation values (R2) were ≥0.99 with phloroglucinol as standard. Direct quantification of TPCs (phloroglucinol equivalents, PGEs) in crude aqueous and ethanolic extracts from A. nodosum demonstrated that the new FBBB assay is not subject to side-redox interference and provides a more accurate estimate of TPC (1.2-3.9-fold lower than with the FC assay) in a relatively rapid (30 min), cost-effective (0.24€/test) microplate format.

Fast Blue and Cholera Toxin-B Survival Guide for Alpha-Motoneurons Labeling: Less Is Better in Young B6SJL Mice, but More Is Better in Aged C57Bl/J Mice.

Fast Blue (FB) and Cholera Toxin-B (CTB) are two retrograde tracers extensively used to label alpha-motoneurons (α-MNs). The overall goals of the present study were to (1) assess the effectiveness of different FB and CTB protocols in labeling α-MNs, (2) compare the labeling quality of these tracers at standard concentrations reported in the literature (FB 2% and CTB 0.1%) versus lower concentrations to overcome tracer leakage, and (3) determine an optimal protocol for labeling α-MNs in young B6SJL and aged C57Bl/J mice (when axonal transport is disrupted by aging). Hindlimb muscles of young B6SJL and aged C57Bl/J mice were intramuscularly injected with different FB or CTB concentrations and then euthanized at either 3 or 5 days after injection. Measurements were performed to assess labeling quality via seven different parameters. Our results show that tracer protocols of lower concentration and shorter labeling durations were generally better in labeling young α-MNs, whereas tracer protocols of higher tracer concentration and longer labeling durations were generally better in labeling aged α-MNs. A 0.2%, 3-day FB protocol provided optimal labeling of young α-MNs without tracer leakage, whereas a 2%, 5-day FB protocol or 0.1% CTB protocol provided optimal labeling of aged α-MNs. These results inform future studies on the selection of optimal FB and CTB protocols for α-MNs labeling in normal, aging, and neurodegenerative disease conditions.

A Colorimetric Method for the Rapid Estimation of the Total Cannabinoid Content in Cannabis Samples.

A colorimetric method for the estimation of the total content of cannabinoids in cannabis samples is proposed. The assay is based on the reaction of these compounds with the reagent Fast Blue B (FBB), which has been immobilized into polydimethylsiloxane (PDMS). The reaction and detection conditions have been established according to the results obtained for the individual cannabinoids Δ9-tetrahydrocannabidiol (THC), cannabidiol (CBD), and cannabinol (CBN), as well as for ethanolic extracts obtained from cannabis samples after ultrasonication. In contact with the extract and under basic conditions, the reagent diffuses from the PDMS device, producing a red-brown solution. The absorbances measured at 500 nm after only 1 min of exposure to the FBB/PDMS composites led to responses proportional to the amounts of the cannabinoids in the reaction media. Those absorbances have been then transformed in total cannabinoid content using CBD as a reference compound. The potential utility of the proposed conditions has been tested by analyzing different cannabis samples. The selectivity towards other plants and drugs has been also evaluated. The present method is proposed as a simple and rapid alternative to chromatographic methods for the estimation of the total content of cannabinoids.

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 7th day. Inflammatory cytokines, interleukin-1ß, and tumor necrosis factor α appeared on the 1st day after intracerebral hemorrhage, reached peak levels on the 3rd day, and decreased from the 7th day. Our findings show the characteristics of the progression of early brainstem hemorrhage.

Staining Methods for Normal and Regenerative Myelin in the Nervous System.

Histochemical and fluorescence-based techniques enable the specific identification of myelin by bright-field or fluorescence microscopy. In this chapter, we describe four histological methods for the evaluation of myelin on peripheral nerve tissue sections. The first method combines the Luxol fast blue (LFB) technique with a modified Picrosirius staining contrasted with Harris hematoxylin, called MCOLL. This method simultaneously stains myelin, collagen fibers, and cell nuclei, thus giving an integrated overview of the histology, collagen network, and myelin content of the tissue in paraffin-embedded or cryosectioned samples. Secondly, we describe the osmium tetroxide method, which provides a permanent positive reaction for myelin as well as other lipids present in the tissue. The third method is the immunofluorescence-based detection of myelin proteins that allows to combine information about their expression status with other proteins of interest. Finally, the FluoroMyelin™ stains enable a fast detection of the myelin content that can be easily implemented in immunofluorescence staining panels for cryosectioned tissues. Together, this chapter provides a variety of methods to accurately identify myelin in different experimental approaches.

Bridging potential of Taurine-loading PCL conduits transplanted with hEnSCs on resected sciatic nerves.

Reconstruction of nerve conduits is a promising method for functional improvement in peripheral nerve repair. Besides choosing of a suitable polymer for conduit construction, adding factors such as Taurine improve a more advantageous microenvironment for defect nerve regeneration. Showing several major biological properties of Taurine, for example, regulation of the osmotic pressure, modulation of neurogenesis, and calcium hemostasis, makes it an appropriate option for repairing of defected nerves. To this, we examined repairing effects of Taurine-loading PCL conduits cultured with human endothelial stem cells (hEnSCs) on resected sciatic nerves. PCL/Taurine/Cell conduits transplanted to a 10-mm sciatic nerve gap. Forty-two wistar rats were randomly divided to seven groups: (1) Normal group, (2) Negative control (NC), (3) Positive control (nerve Autograft group), (4) PCL conduits group (PCL), (5) Taurine loaded PCL conduits group (PCL/Taurine), (6) hEnSCs cultured on the PCL conduits (PCL/Cell), (7) hEnSCs cultured on the PCL/Taurine conduits (PCL/Taurine/Cell). Functional recovery of motor and sensory nerves, the action potential of exciting muscle and motor distal latency has seen in PCL/Taurine/Cell conduits. Histological studies showed also remarkable nerve regeneration and obvious bridging has seen in this group. In conclusion, PCL/Taurine/Cell conduits showing suitable mechanical properties and biocompatibility may improve sciatic nerve regeneration.

Interpretable deep learning of myelin histopathology in age-related cognitive impairment.

Age-related cognitive impairment is multifactorial, with numerous underlying and frequently co-morbid pathological correlates. Amyloid beta (Aß) plays a major role in Alzheimer's type age-related cognitive impairment, in addition to other etiopathologies such as Aß-independent hyperphosphorylated tau, cerebrovascular disease, and myelin damage, which also warrant further investigation. Classical methods, even in the setting of the gold standard of postmortem brain assessment, involve semi-quantitative ordinal staging systems that often correlate poorly with clinical outcomes, due to imperfect cognitive measurements and preconceived notions regarding the neuropathologic features that should be chosen for study. Improved approaches are needed to identify histopathological changes correlated with cognition in an unbiased way. We used a weakly supervised multiple instance learning algorithm on whole slide images of human brain autopsy tissue sections from a group of elderly donors to predict the presence or absence of cognitive impairment (n = 367 with cognitive impairment, n = 349 without). Attention analysis allowed us to pinpoint the underlying subregional architecture and cellular features that the models used for the prediction in both brain regions studied, the medial temporal lobe and frontal cortex. Despite noisy labels of cognition, our trained models were able to predict the presence of cognitive impairment with a modest accuracy that was significantly greater than chance. Attention-based interpretation studies of the features most associated with cognitive impairment in the top performing models suggest that they identified myelin pallor in the white matter. Our results demonstrate a scalable platform with interpretable deep learning to identify unexpected aspects of pathology in cognitive impairment that can be translated to the study of other neurobiological disorders.

Treatment With Nimodipine or FK506 After Facial Nerve Repair Neither Improves Accuracy of Reinnervation Nor Recovery of Mimetic Function in Rats.

Purpose: Nimodipine and FK506 (Tacrolimus) are drugs that have been reported to accelerate peripheral nerve regeneration. We therefore tested these substances aiming to improve the final functional outcome of motoric reinnervation after facial nerve injury. Methods: In 18 female rats, the transected facial nerve was repaired by an artificial nerve conduit. The rats were then treated with either placebo, nimodipine, or FK506, for 56 days. Facial motoneurons were pre-operatively double-labeled by Fluoro-Gold and again 56 days post-operation by Fast-Blue to measure the cytological accuracy of reinnervation. The whisking motion of the vibrissae was analyzed to assess the quality of functional recovery. Results: On the non-operated side, 93-97% of those facial nerve motoneurons innervating the vibrissae were double-labeled. On the operated side, double-labeling only amounted to 38% (placebo), 40% (nimodipine), and 39% (FK506), indicating severe misdirection of reinnervation. Regardless of post-operative drug or placebo therapy, the whisking frequency reached 83-100% of the normal value (6.0 Hz), but whisking amplitude was reduced to 33-48% while whisking velocity reached 39-66% of the normal values. Compared to placebo, statistically neither nimodipine nor FK506 improved accuracy of reinnervation and function recovery. Conclusion: Despite previous, positive data on the speed and quantity of axonal regeneration, nimodipine and FK506 do not improve the final functional outcome of motoric reinnervation in rats.

At least four distinct blue cationic phthalocyanine dyes sold as "alcian blue" raises the question: what is alcian blue?

We investigated physicochemical characteristics of dye lots sold as "alcian blue" using the Biological Stain Commission (BSC) precipitation test, differential scanning calorimetry, high performance liquid chromatography, thin layer chromatography and UV/visible spectroscopy. Four blue phthalocyanine dyes were detected in 11 commercial dye lots. These four included the original ingrain blue 1 CI 74000 dye and the dye sold with the name "alcian blue pyridine variant"; we discuss also the possible identity of the additional two dyes. A proposed extension to the BSC analytic scheme is presented that could distinguish three categories of commercial alcian blue dyes from each other and from the original alcian blue 8G.

E-Learning Three-Dimensional Anatomy of the Brainstem: Impact of Different Microscopy Techniques and Spatial Ability.

Polarized light imaging (PLI) is a new method which quantifies and visualizes nerve fiber direction. In this study, the educational value of PLI sections of the human brainstem were compared to histological sections stained with Luxol fast blue (LFB) using e-learning modules. Mental Rotations Test (MRT) was used to assess the spatial ability. Pre-intervention, post-intervention, and long-term (1 week) anatomical tests were provided to assess the baseline knowledge and retention. One-on-one electronic interviews after the last test were carried out to understand the students' perceptions of the intervention. Thirty-eight medical students, (19 female and 19 males, mean age 21.5 ± SD 2.4; median age: 21.0 years) participated with a mean MRT score of 13.2 ± 5.2 points and a mean pre-intervention knowledge test score of 49.9 ± 11.8%. A significant improvement in both, post-intervention and long-term test scores occurred after learning with either PLI or LFB e-learning module on brainstem anatomy (both P < 0.001). No difference was observed between groups in post-intervention test scores and long-term test scores (P = 0.913 and P = 0.403, respectively). A higher MRT-score was significantly correlated with a higher post-intervention test score (rk  = 0.321; P < 0.05, respectively), but there was not a significant association between the MRT- and the long-term scores (rk = -0.078; P = 0.509). Interviews (n = 10) revealed three major topics: Learning (brainstem) anatomy by use of e-learning modules; The "need" of technological background information when studying brainstem sections; and Mnemonics when studying brainstem anatomy. Future studies should assess the cognitive burden of cross-sectional learning methods with PLI and/or LFB sections and their effects on knowledge retention.

Accurate determination of total biophenols in unfractionated extra-virgin olive oil with the fast blue BB assay.

The phenolic compounds of extra-virgin olive oil (EVOO) are key contributors of nutritional and sensory quality as well as chemical stability. The reference method for their determination is the HPLC-UV, which is cost-/time-expensive. In this work, total phenolic compounds were evaluated in unfractionated EVOO adapting the Fast Blue BB (FBBB) assay, which involves the spectrophotometric (absorbance at 420 nm) determination of azo derivatives resulting from the coupling of phenolic compounds with FBBB diazonium salt in alkali pH. When tested on 26 EVOO samples, the FBBB assay and HPLC-determinations were strikingly correlated (R2 = 0.9653), differently from FBBB and Folin-Ciocalteu assays, which showed poor correlation. The assay is simple, repeatable, robust, rapid and cheap, and results might be evaluated on a printed colorimetric scale. This protocol of the FBBB assay could be routinely used to categorize EVOO according to the health claim allowed by EFSA concerning the content of phenolic compounds.

Optimization of Extraction Solvent and Fast Blue BB Assay for Comparative Analysis of Antioxidant Phenolics from Cucumis melo L.

Melon (Cucumis melo L.) fruits contain multiple health-promoting compounds, including phenolic compounds, which are antioxidants. Accurate measurement of antioxidant activities and total phenolic contents (TPCs) require an efficient solvent extraction. In this study, we evaluated free radical scavenging activity and TPC of melon extracts extracted with 22 different solvent combinations. The DPPH scavenging activities were high in 100% methanolic (39.48 ± 0.36 µg g-1) and 80% methanolic extracts (38.99 ± 0.44 µg g-1). Similarly, the ABTS scavenging activities were high in 100% methanolic (315.11 ± 10.38 µg g-1) and 80% methanol extracts (297.39 ± 14.98 µg g-1). The Folin-Ciocalteu (F-C) assay is typically used to measure TPC but may be affected by interference from sugars and other compounds. Therefore, we optimized an assay for TPC using Fast Blue (FB) salt and developed a standard operating procedure for microplate analysis using FB. Our analysis of standard samples and comparisons with the F-C assay suggested that the optimized FB assay could be used to measure TPC in fruit and juice samples. Moreover, we successfully detected six phenolic compounds in methanol extracts of melon by LC-HR-QTOF/MS.

5-HT7 receptor activation rescues impaired synaptic plasticity in an autistic-like rat model induced by prenatal VPA exposure.

Autism spectrum disorder (ASD) is a severe life-long neuropsychiatric disorder. Alterations and imbalance of several neurochemical systems may be involved in ASD pathophysiology, of them, serotonergic neurotransmission dysfunction and deficiency may underlie behavioral abnormalities associated with ASD. However, the functional importance of serotonergic receptors, particularly 5HT7 receptors in ASD pathology remains poorly defined. Serotonin receptor subtype 7 (5-HT7R) plays a direct regulatory role in the development and also for the mature function of the brain, therefore, further studies are necessary to elucidate the role of these receptors in the etiology of autism. To address this issue, we combined here behavioral, electrophysiological methods to further characterize the contribution of 5-HT7Rs in the prenatal valproic acid (VPA) exposure-induced impairment in synaptic plasticity and their impact on the associated behavioral changes. This may help to unravel the underlying cellular mechanisms involved in ASD and can lead to new treatment and/or prevention therapies based on the role of the serotonergic system for autism. Findings revealed that compared to control, autistic-like offspring showed increased anxiety-like behavior, reduced social interaction, decreased locomotor activity, and impaired identification of the novel object. However, administration of 5-HT7Rs agonist, LP-211, for 7 consecutive days before testing from postnatal day 21 to 27 reversed all behavioral deficits induced by prenatal exposure to VPA in offspring. Also, both short-term depression and long-term potentiation were impaired in the autistic-like pups, but activation of 5-HT7Rs rescued the LTP impairment in the autistic-like group so that there was no significant difference between the two groups. Blockade of 5-HT7Rs caused LTP impairment following HFS in the autistic-like group. Besides, there was a significant difference in LTD induction following SB-269970 application between the control and the autistic-like groups measured at first 10 min following TPS. Moreover, both the number and the size of retrograde fast blue-labelled neurons in the raphe nuclei were reduced. Overall, these results provide for the first time, as far as we know, functional evidence for the restorative role of 5-HT7Rs activation against prenatal VPA exposure induced behavioral deficits and hippocampal synaptic plasticity impairment. Therefore, these receptors could be a potential and promising pharmacotherapy target for the treatment of autism.

Color determination method and evaluation of methods for the detection of cannabinoids by thin-layer chromatography (TLC).

Cannabis sativa is the drug of abuse most cultivated, trafficked, and consumed worldwide. One of several techniques used to detect cannabinoids is based on the thin-layer chromatography (TLC). However, the designation of the colors observed can be inaccurate and not reproducible. The designation of colors goes beyond physical and physiological aspects, because what is conventionally called color is a socio-cultural construction. Thus, the objective of this paper was to evaluate the different TLC methods to detection of cannabinoids, and apply standardization method in naming of colors. TLC analysis performed using silica gel 60 F254 as a stationary phase. Three mobile phase compositions [hexane:chloroform (8:2 v:v), hexane:ethyl ether (8:2 v:v), and chloroform:hexane (8:2 v:v)], as well as, two different solutions of Fast Blue B salt (FBBS, Azoic Diazo No. 48) and Fast Blue RR (FBRR, Azoic Diazo No. 24) were evaluated. Determination of colors names was realized through the Sci-Chromus® software. The best resolution was obtained using hexane:ethyl ether (8:2 v:v) as a mobile phase. It was observed that although the cannabidiol (CBD), delta-9-tetrahydrocannabinol (Δ9 -THC), cannabinol (CBN), and cannabigerol (CBG) were detect using both the FBBS- and FBRR-acidified solutions, the best visualization was achieved using the latter reagent. To the best of our knowledge, this is the first study that applied and demonstrated a method for standardization and denomination of colors in the TLC analysis of cannabinoids. This method was able to reduce the subjectivity in naming the colors observed and presented several application possibilities.

Expression of phosphatidylinositol 3-kinase/protein kinase B/FoxOl signal pathway and interleukin-17 in experimental autoimmune encephalomyelitis in mice / 解剖学报

Objective To investigate the relevant mechanisms of phosphatidylinositol 3-kinase (PI3K) /protein kinase B (Akt)/Fox01 and interleukin-17 (IL-17) in the oneset of experimental autoimmune encephalomyelitis (EAE) mice. Methods Sixty C57BL/6 mice were randomly divided into control group and model group (EAE), 30 in each group. The EAE model was induced by myelin oligodendrocyte glycoprotein ( MOG

The modified method of luxol fast blue for paraffin-embedded myelin sheath staining / El método modificado de luxol fast blue para la tinción de mielina fijada en parafina

SUMMARY: Histological techniques are the study of animal and human tissues through staining and examining them under a microscope. To demonstrate the axonal degeneration and demyelination in histological studies, the Luxol Fast Blue staining is gold standard techniques. In this study, a new histochemical method based on modified Luxol Fast Blue for the staining of the myelin sheath in sciatic nerve tissues described. The sciatic nerves of rats were removed and then the sciatic nerve was immersed in 10 % formaldehyde for one week and embedded in paraffin block. Next, thin sections (5 µm) were cut, using a microtome and stained with conventional and modified Luxol Fast Blue. Our results showed that a new method of modified Luxol Fast Blue staining can accurately identify the myelin in the sciatic nerve fibers. The current study showed that the Luxol Fast Blue combination with Light Green has a good effect on myelin coloration, and the results of this study are comparable to LFB combination with Sirius red.

RESUMEN: Las técnicas histológicas son el estudio de tejidos animales y humanos mediante tinción y examen bajo un microscopio. Para demostrar la degeneración axonal y la desmielinización en estudios histológicos, la tinción Luxol Fast Blue es una técnica estándar de oro. En este estudio, se describe un nuevo método histoquímico basado en Luxol Fast Blue modificado para la tinción de mielina en los tejidos del nervio ciático. Se seccionaron los nervios ciáticos de ratas y luego el nervio ciático se sumergió en formaldehído al 10 % durante una semana y se fijó en bloque de parafina. Posteriormente, se cortaron secciones delgadas (5 µm) usando un microtomo y se tiñeron con Luxol Fast Blue convencional y modificado. Nuestros resultados mostraron que un nuevo método de tinción Luxol Fast Blue modificado puede identificar con precisión la mielina en las fibras del nervio ciático. El estudio actual mostró que la combinación Luxol Fast Blue con Light Green es un buen efecto sobre la coloración de mielina, y los resultados de este estudio son comparables a la combinación LFB con Sirius red.

Certification procedures used by the Biological Stain Commission for eriochrome cyanine R (C.I. 43820, Mordant blue 3).

Eriochrome cyanine R (C.I. 43820, Mordant blue 3), also known as chromoxane cyanine R and solochrome cyanine R, has been used as a biological stain since 1957. In conjunction with ferric ions, it provides selective blue coloration of the nuclei of cells in methods procedurally similar to commonly used progressive or regressive hemalum (aluminum-hematoxylin) stains. Eriochrome cyanine R also is used to stain the myelin sheaths of axons in nerve tissue; the results are visually similar to those in sections stained with luxol fast blue MBS (C.I. 74180, solvent blue 38) with selective blue coloration of myelin and erythrocytes. Eriochrome cyanine R is an article of commerce with many uses in industrial coloration and analytical chemistry; it can be used instead of either hematoxylin or luxol fast blue MBS, especially in the event of a shortage of either of the latter compounds. The Biological Stain Commission (BSC) will certify batches of eriochrome cyanine R that meet the criteria set out in this document. The criteria include satisfactory UV/visible spectra at pH 4 and pH 12 - 13, a dye content not less than 40% and not greater than 52% (calculated as the color acid; equivalent to 46 - 59% of the trisodium salt), and satisfactory performance in three staining methods: regressive for nuclei, progressive for nuclei and regressive for myelin.

Recovery of sensory function after the implantation of oriented-collagen tube into the resected rat sciatic nerve.

INTRODUCTION: In the present study, we examined the effect of oriented collagen tube (OCT) implantation on the recovery of sensory function of the resected rat sciatic nerve. MATERIALS AND METHODS: After a 10-mm long portion of the sciatic nerve of a rat was resected, an OCT was placed in the site of nerve defect. Recovery of the sensory function was evaluated using Von Frey test every 3 days after surgery. The regenerated tissue were histologically and ultrastructurally analyzed 2 and 4 weeks after the surgery. RESULTS: The sensory reflexes of the OCT group were restored to the level of that of the intact group after 15 days. Hematoxylin and eosin staining revealed the cross-linking between the proximal and distal stumps after 2 weeks. After 4 weeks, Luxol Fast Blue and immunohistochemical staining revealed the presence of myelin sheath from the proximal to distal region of the regenerated tissue and S100B staining confirmed the presence of Schwann cells. Interestingly, no myelin sheath was ultrastructurally observed around the regenerated axons at the central region after 2 weeks. CONCLUSIONS: These results suggest that OCTs facilitate the recovery of sensory function. Additionally, the non-myelinated axons contributed to the recovery of the sensory function.

A novel model of cerebral hyperperfusion with blood-brain barrier breakdown, white matter injury, and cognitive dysfunction.

OBJECTIVE: Cerebral hyperperfusion (CHP) is associated with considerable morbidity. Its pathophysiology involves disruption of the blood-brain barrier (BBB) with subsequent events such as vasogenic brain edema and ischemic and/or hemorrhagic complications. Researchers are trying to mimic the condition of CHP; however, a proper animal model is still lacking. In this paper the authors report a novel surgically induced CHP model that mimics the reported pathophysiology of clinical CHP including BBB breakdown, white matter (WM) injury, inflammation, and cognitive impairment. METHODS: Male Sprague-Dawley rats were subjected to unilateral common carotid artery (CCA) occlusion and contralateral CCA stenosis. Three days after the initial surgery, the stenosis of CCA was released to induce CHP. Cortical regional cerebral blood flow was measured using laser speckle flowmetry. BBB breakdown was assessed by Evans blue dye extravasation and matrix metalloproteinase-9 levels. WM injury was investigated with Luxol fast blue staining. Cognitive function was assessed using the Barnes circular maze. Other changes pertaining to inflammation were also assessed. Sham-operated animals were prepared and used as controls. RESULTS: Cerebral blood flow was significantly raised in the cerebral cortex after CHP induction. CHP induced BBB breakdown evident by Evans blue dye extravasation, and matrix metalloproteinase-9 was identified as a possible culprit. WM degeneration was evident in the corpus callosum and corpus striatum. Immunohistochemistry revealed macrophage activation and glial cell upregulation as an inflammatory response to CHP in the striatum and cerebral cortex. CHP also caused significant impairments in spatial learning and memory compared with the sham-operated animals. CONCLUSIONS: The authors report a novel CHP model in rats that represents the pathophysiology of CHP observed in various clinical scenarios. This model was produced without the use of pharmacological agents; therefore, it is ideal to study the pathology of CHP as well as to perform preclinical drug trials.