Lesioned Rat Model Research Articles

A2AR antagonists triggered the AMPK/m-TOR autophagic pathway to reverse the calcium-dependent cell damage in 6-OHDA induced model of PD

Calcium dyshomeostasis, oxidative stress, autophagy and apoptosis are the pathogenesis of selective dopaminergic neuronal loss in Parkinson's disease (PD). Earlier, we reported that A2A R modulates IP3-dependent intracellular Ca2+ signalling via PKA. Moreover, A2A R antagonist has been reported to reduce oxidative stress and apoptosis in PD models, however intracellular Ca2+ ([Ca2+]i) dependent autophagy regulation in the 6-OHDA model of PD has not been explored. In the present study, we investigated the A2A R antagonists mediated neuroprotective effects in 6-OHDA-induced primary midbrain neuronal (PMN) cells and unilateral lesioned rat model of PD. 6-OHDA-induced oxidative stress (ROS and superoxide) and [Ca2+]i was measured using Fluo4AM, DCFDA and DHE dye respectively. Furthermore, autophagy was assessed by Western blot of p-m-TOR/mTOR, p-AMPK/AMPK, LC3I/II, Beclin and β-actin. Apoptosis was measured by Annexin V-APC-PI detection and Western blot of Bcl2, Bax, caspase3 and β-actin. Dopamine levels were measured by Dopamine ELISA kit and Western blot of tyrosine hydroxylase. Our results suggest that 6-OHDA-induced PMN cell death occurred due to the interruption of [Ca2+]i homeostasis, accompanied by activation of autophagy and apoptosis. A2A R antagonists prevented 6-OHDA-induced neuronal cell death by decreasing [Ca2+]i overload and oxidative stress. In addition, we found that A2A R antagonists upregulated mTOR phosphorylation and downregulated AMPK phosphorylation thereby reducing autophagy and apoptosis both in 6-OHDA induced PMN cells and 6-OHDA unilateral lesioned rat model. In conclusion, A2A R antagonists alleviated 6-OHDA toxicity by modulating [Ca2+]i signalling to inhibit autophagy mediated by the AMPK/mTOR pathway.

AMPK-mediated autophagy pathway activation promotes ΔFosB degradation to improve levodopa-induced dyskinesia

BackgroundParkinson's disease patients on chronic levodopa often suffer from motor complications, which tend to reduce their quality of life. Levodopa-induced dyskinesia (LID) is one of the most prevalent motor complications, often characterized by abnormal involuntary movements, and the pathogenesis of LID is still unclear but recent studies have suggested the involvement of autophagy. MethodsThe onset of LID was mimicked by chronic levodopa treatment in a unilateral 6-hydroxydopamine (6-OHDA) -lesion rat model. Overexpression of ΔFosB in HEK293 cells to mimic the state of ΔFosB accumulation. The modulation of the AMP-activated protein kinase (AMPK)-mediated autophagy pathway using by metformin, AICAR (an AMPK activator), Compound C (an AMPK inhibitor) and chloroquine (an autophagy pathway inhibitor). The severity of LID was assessed by axial, limb, and orofacial (ALO) abnormal involuntary movements (AIMs) score and in vivo electrophysiology. The activity of AMPK pathway as well as autophagy markers and FosB-ΔFosB levels were detected by western blotting. RT-qPCR was performed to detect the transcription level of FosB-ΔFosB. The mechanism of autophagy dysfunction was further explored by immunofluorescence and transmission electron microscopy. ResultsIn vivo experiments demonstrated that chronic levodopa treatment reduced AMPK phosphorylation, impaired autophagosome-lysosomal fusion and caused FosB-ΔFosB accumulation in the striatum of PD rats. Long-term metformin intervention improved ALO AIMs scores as well as reduced the mean power of high gamma (hγ) oscillations and the proportion of striatal projection neurons unstable in response to dopamine for LID rats. Moreover, the intervention of metformin promoted AMPK phosphorylation, ameliorated the impairment of autophagosome-lysosomal fusion, thus, promoting FosB-ΔFosB degradation to attenuate its accumulation in the striatum of LID rats. However, the aforementioned roles of metformin were reversed by Compound C and chloroquine. The results of in vitro studies demonstrated the ability of metformin and AICAR to attenuate ΔFosB levels by promoting its degradation, while Compound C and chloroquine could block this effect. ConclusionsIn conclusion, our results suggest that long-term metformin treatment could promote ΔFosB degradation and thus attenuate the development of LID through activating the AMPK-mediated autophagy pathway. Overall, our results support the AMPK-mediated autophagy pathway as a novel therapeutic target for LID and also indicate that metformin is a promising therapeutic candidate for LID.

Molecular interaction analysis of anti-IL-8 scFv-10F8-6His against IL-8 monomer through molecular docking and molecular dynamic simulations

Elevated interleukin 8 (IL-8) expression has been linked to unfavorable outcomes in a range of inflammatory conditions, such as rheumatoid arthritis, psoriasis, and cancer. The human monoclonal antibody (HuMab) 10F8 and the hybridoma 35B11-B bind to an epitope on human IL-8, respectively. 10F8 inhibited interaction between IL-8 and neutrophils in eczema and pustulosis palmoplantaris patients while 35B11-B decreased size lesion in rat model. The binding interaction of monoclonal antibodies and IL-8, especially how complementarity-determining region (CDR) loops could bind the N-terminal of IL-8, has not been fully deliberated at molecular-level. Here, we used a combination of molecular docking, heated and long coarse-grained molecular dynamics simulations to identify key residues of established interaction. Based on heated MD simulation, docked pose of complexes generated by ClusPro showed good binding stability throughout of 70 ns simulation. Based on long molecular dynamic simulations, key residues for the binding were identified throughout of 1000 ns simulation. TYR-53, ASP-99, and ARG-100 of heavy chain CDR together with TYR-33 of light chain CDR are among the highest contributing energy residues within the binding interaction. Meanwhile, LYS11 and TYR13 of IL-8 are important for the determination of overall binding energy. Furthermore, the result of decomposition residues analysis is in good agreement with the interaction analysis data. Current study provides a list of important interacting residues and further scrutiny on these residues is essential for future development and design of a new and stable recombinant antibody against IL-8. Communicated by Ramaswamy H. Sarma

Neurobehavioral Evaluation Of Ethanolic extracts from Newbouldia Laevis leaf in 6-hydroxyldopamine- lesioned rat model of Parkinson’s disease treated with L-DOPA

Neurobehavioral Evaluation Of Ethanolic extracts from Newbouldia Laevis leaf in 6-hydroxyldopamine- lesioned rat model of Parkinson’s disease treated with L-DOPA

Periaqueductal grey and spinal cord pathology contribute to pain in Parkinson’s disease

Pain is a key non-motor feature of Parkinson’s disease (PD) that significantly impacts on life quality. The mechanisms underlying chronic pain in PD are poorly understood, hence the lack of effective treatments. Using the 6-hydroxydopamine (6-OHDA) lesioned rat model of PD, we identified reductions in dopaminergic neurons in the periaqueductal grey (PAG) and Met-enkephalin in the dorsal horn of the spinal cord that were validated in human PD tissue samples. Pharmacological activation of D1-like receptors in the PAG, identified as the DRD5+ phenotype located on glutamatergic neurons, alleviated the mechanical hypersensitivity seen in the Parkinsonian model. Downstream activity in serotonergic neurons in the Raphé magnus (RMg) was also reduced in 6-OHDA lesioned rats, as detected by diminished c-FOS positivity. Furthermore, we identified increased pre-aggregate α-synuclein, coupled with elevated activated microglia in the dorsal horn of the spinal cord in those people that experienced PD-related pain in life. Our findings have outlined pathological pathways involved in the manifestation of pain in PD that may present targets for improved analgesia in people with PD.

Acellular Biomaterials Associated with Autologous Bone Marrow-Derived Mononuclear Stem Cells Improve Wound Healing through Paracrine Effects

Wound healing is a complex process of repair that involves the interaction between different cell types and involves coordinated interactions between intracellular and extracellular signaling. Bone Marrow Mesenchymal Stem Cells (BMSCs) based and acellular amniotic membrane (AM) therapeutic strategies with the potential for treatment and regeneration of tissue. We aimed to evaluate the involvement of paracrine effects in tissue repair after the flap skin lesion rat model. In the full-thickness flap skin experiment of forty Wistar rats: A total of 40 male Wistar rats were randomized into four groups: group I: control (C; n = 10), with full-thickness lesions on the back, without (BMSCs) or AM (n = 10); group II: injected (BMSCs; n = 10); group III: covered by AM; group IV-injected (AM + BMSCs; n = 10). Cytokine levels, IL-1, and IL-10 assay kits, superoxide dismutase (SOD), glutathione reductase (GRs) and carbonyl activity levels were measured by ELISA 28th day, and TGF-β was evaluated by immunohistochemical, the expression collagen expression was evaluated by Picrosirius staining. Our results showed that the IL-1 interleukin was higher in the control group, and the IL-10 presented a higher mean when compared to the control group. The groups with BMSCs and AM showed the lowest expression levels of TGF-β. SOD, GRs, and carbonyl activity analysis showed a predominance in groups that received treatment from 80%. The collagen fiber type I was predominant in all groups; however, the AM + BMSCs group obtained a higher average when compared to the control group. Our findings suggest that the AM+ BMSCs promote skin wound healing, probably owing to their paracrine effect attributed to the promotion of new collagen for tissue repair.

Creating a diabetic model with skin wounds in rats for application in wound treatment

Chronic limb ulcer is one of many dangerous complications of diabetes mellitus. Creating a skin lesion model in rats with diabetes and hyperlipidemia opens the door for testing new treatments in clinical practice. Wistar male rats were induced to have diabetes and dyslipidemia using a high-fat diet for six weeks and low-doses Streptozocin (STZ) injections (35 mg/kg). After that, skin wounds were created by cutting the total skin layer; observation of healing process and histopathological assessment were conducted. The results showed that rats fed with a high-fat diet combined with low-dose STZ injection induced hyperlipidemia and hyperglycemia that remained above 11 mmol/L during the follow-up period. The diabetic and hyperlipidemic rats had longer wound healing time than the normal rats. Thus, this study successfully created an excisional skin wound model on Wistar rats with diabetes and hyperlipidemia which could serve in future testing phases of new wound healing treatments.

Characterizing the relationship between L-DOPA-induced-dyskinesia and psychosis-like behaviors in a bilateral rat model of Parkinson's disease

Parkinson's disease associated psychosis (PDAP) is a prevalent non-motor symptom (NMS) that significantly erodes patients' and caregivers' quality of life yet remains vastly understudied. One potential source of PDAP in late-stage Parkinson's disease (PD) is the common dopamine (DA) replacement therapy for motor symptoms, Levodopa (L-DOPA). Given the high incidence of L-DOPA-induced dyskinesia (LID) in later phases of PD, this study sought to characterize the relationship between PDAP and LID in a bilateral medial forebrain bundle 6-hydroxydopamine hydrobromide (6-OHDA) lesion rat model. To assess PDAP in this model, prepulse inhibition (PPI), a well-validated assay of sensorimotor gating, was employed. First, we tested whether a bilateral lesion alone or after chronic L-DOPA treatment was sufficient to induce PPI dysfunction. Rats were also monitored for LID development, using the abnormal involuntary movements (AIMs) test, to examine PPI and LID associations. In experiment 2, Vilazodone (VZD), a serotonin transporter (SERT) blocker and 1A receptor (5-HT1A) partial agonist was administered to test its potential efficacy in reducing LID and PPI dysfunction. Once testing was complete, tissue was collected for high performance liquid chromatography (HPLC) to examine the monoamine levels in motor and non-motor circuits. Results indicate that bilateral DA lesions produced motor deficits and that chronic L-DOPA induced moderate AIMs; importantly, rats that developed more severe AIMs were more likely to display sensorimotor gating dysfunction. In addition, VZD treatment dose-dependently reduced L-DOPA-induced AIMs without impairing L-DOPA efficacy, although VZD's effects on PPI were limited. Altogether, this project established the bilateral 6-OHDA lesion model accurately portrayed LID and PDAP-like behaviors, uncovered their potential relationship, and finally, demonstrated the utility of VZD for reducing LID.

Design and synthesis of benzo[d]thiazol-2-yl-methyl-4-(substituted)-piperazine-1-carbothioamide as novel neuronal nitric oxide inhibitors and evaluation of their neuroprotecting effect in 6-OHDA-induced unilateral lesioned rat model of Parkinson's disease

Neuronal nitric oxide synthase (nNOS) is an enzyme constitutively expressed in the mammalian brain and skeletal muscles. The excessive activation of nNOS in the neurons results in oxidative and nitrosative stress associated with neuronal loss in various neurological disorders. Several nNOS inhibitors have been reported to limit the excessive activation of nNOS. In the present work, we have designed and carried the synthesis of benzo[d]thiazol-2-yl-methyl-4-(substituted)-piperazine-1-carbothioamide as novel neuronal nitric oxide inhibitors (5–28, twenty-four compounds). Stably transfected HEK 293 cells expressing NOS isoforms treated with the compounds (5–28) showed that the eight compounds exhibited > 95% cell survival in the MTT assay. nNOS inhibition assay of the eight compounds illustrated that the compound 18 was most selective for nNOS (nNOS=66.73 ± 1.51; eNOS=28.70 ± 1.39; iNOS =13.26 ± 1.01) in HEK 293 cells expressing NOS isoforms. 6-OHDA-induced unilaterally lesioned rats treated with the compound 18 showed the improvement in motor and non-motor functions. Furthermore, the compound 18 showed the increased levels of dopamine and decreased levels of glutamate and nitrite ions in the isolated rat brain. In the docking analysis, the compound 18 showed the significant binding affinity with the nNOS binding site (the ∆G value = - 9.0 kcal/mol). Overall results demonstrated that the N-(benzo[d]thiazol-2-ylmethyl)-4-(4-nitrophenyl) piperazine-1-carbothioamide (the compound 18) possessed significant nNOS inhibiting activity and neuroprotecting potential in 6-OHDA-induced unilaterally lesioned rat model of PD and more work will be required to establish the role of the compound 18 in the therapy of PD and other neurodegenerative disorders.

Therapeutic Potential of Low-Intensity Magnetic Field Stimulation in 6-Hydroxydopamine Rat Model of Parkinson's Disease: From Inflammation to Motor Function.

Parkinson's disease (PD) is a progressive neurodegenerative disorder that mainly affects the aged population. Transcranial magnetic field (MF) stimulation has shown to provide temporary motor recovery in neurological disorders. The aim of this study was to understand the cellular and molecular mechanism of low-intensity MF stimulation (17.96 µT; 50Hz; 2 h/day, four weeks) in a rat model of severe PD. A clinically relevant, bilateral striatal 6-hydroxydopamine (6-OHDA) lesioned rat model of severe PD was employed to test the efficacy of low-intensity MF stimulation in the management of motor symptoms. The mechanism of action of MF was dissected by assessing the microglial activation, tissue ultrastructure, and cerebrospinal fluid (CSF) metabolomics using microdialysis. We observed a significant improvement in the postural balance and gait after MF exposure with a significant reduction in the number of activated microglia. There was an improvement in striatal dopaminergic innervation and glutamate levels but it did not reach a level of statistical significance. MF stimulation helped ameliorate the motor deficits and reduced inflammation but was unable to provide a significant change in terms of dopaminergic innervation and metabolic profile in the severe 6-OHDA PD rat model.

Glutamine and GABA alterations in cingulate cortex may underlie alcohol drinking in a rat model of co-occurring alcohol use disorder and schizophrenia: an 1H-MRS study

Alcohol use disorder commonly occurs in patients with schizophrenia and significantly worsens the clinical course of the disorder. The neurobiological underpinnings of alcohol drinking are not well understood. Magnetic resonance spectroscopy (MRS) has been used to assess the neurochemical substrates that may be associated with alcohol drinking in patients; however, the causal impact of these findings remains elusive, highlighting the need for studies in animal models. This study performed MRS in the neonatal ventral hippocampal lesioned (NVHL) rat model, a model of co-occurring schizophrenia and substance use disorders. NVHL lesions (or sham surgeries) were performed on post-natal day 7 and animals were given brief exposure to alcohol during adolescence (10% v/v in a 2-bottle choice design). Animals were re-exposed to alcohol during adulthood (20% v/v) until a stable drinking baseline was established, and then forced into abstinence to control for the effects of differential alcohol drinking. Animals were scanned for MRS after one month of abstinence. NVHL rats consumed significantly more alcohol than sham rats and in the cingulate cortex showed significantly higher levels of GABA and glutamine. Significantly lower GABA levels were observed in the nucleus accumbens. No differences between the NVHL and sham animals were observed in the hippocampus. Correlation analysis revealed that GABA and glutamine concentrations in the cingulate cortex significantly correlated with the rats’ alcohol drinking prior to 30 days of forced abstinence. These findings suggest that a potential dysfunction in the glutamate/GABA–glutamine cycle may contribute to alcohol drinking in a rat model of schizophrenia, and this dysfunction could be targeted in future treatment-focused studies.

Synergistic effect of serotonin 1A and serotonin 1B/D receptor agonists in the treatment of L-DOPA-induced dyskinesia in 6-hydroxydopamine-lesioned rats

BackgroundThe gold standard for symptomatic relief of Parkinson's disease (PD) is L-DOPA. However, long-term treatment often leads to motor complications such as L-DOPA-induced dyskinesia (LID). While amantadine (Gocovri™) is the only approved therapy for dyskinesia in PD patients on the American market, it is associated with neurological side effects and limited efficacy. Thus, there remains a high unmet need for addressing LID in PD patients worldwide. ObjectiveThe objective of this study was to evaluate the efficacy, safety and performance compared to approved treatments of the serotonin receptor 1A (5-HT1A) and 5-HT1B/D agonists buspirone and zolmitriptan in the 6-hydroxydopamine unilaterally lesioned rat model for PD. MethodsThe hemiparkinsonian 6-OHDA-lesioned rats underwent chronic treatment with L-DOPA to induce dyskinesia and were subsequently used for efficacy testing of buspirone, zolmitriptan and comparison with amantadine, measured as abnormal involuntary movement (AIM) scores after L-DOPA challenge. Safety testing was performed in model and naïve animals using forelimb adjusting, rotarod and open field tests. Results5-HT1A and 5-HT1B/D agonism effectively reduced AIM scores in a synergistic manner. The drug combination of buspirone and zolmitriptan was safe and did not lead to tolerance development following sub-chronic administration. Head-to-head comparison with amantadine showed superior performance of buspirone and zolmitriptan in the model. ConclusionsThe strong anti-dyskinetic effect found with combined 5-HT1A and 5-HT1B/D agonism renders buspirone and zolmitriptan together a meaningful treatment for LID in PD.

Cannabinoid Receptors and Glial Response Following a Basal Forebrain Cholinergic Lesion.

The endocannabinoid system modulates learning, memory, and neuroinflammatory processes, playing a key role in neurodegeneration, including Alzheimer's disease (AD). Previous results in a rat lesion model of AD showed modulation of endocannabinoid receptor activity in the basalo-cortical pathway following a specific lesion of basal forebrain cholinergic neurons (BFCNs), indicating that the glial neuroinflammatory response accompanying the lesion is related to endocannabinoid signaling. In this study, 7 days after the lesion, decreased astrocyte and increased microglia immunoreactivities (GFAP and Iba-1) were observed, indicating microglia-mediated neuroinflammation. Using autoradiographic studies, the density and functional coupling to G-proteins of endocannabinoid receptor subtypes were studied in tissue sections from different brain areas where microglia density increased, using CB1 and CB2 selective agonists and antagonists. In the presence of the specific CB1 receptor antagonist, SR141716A, [3H]CP55,940 binding (receptor density) was completely blocked in a dose-dependent manner, while the selective CB2 receptor antagonist, SR144528, inhibited binding to 25%, at best. [35S]GTPγS autoradiography (receptor coupling to Gi/0-proteins) evoked by CP55,940 (CB1/CB2 agonist) and HU308 (more selective for CB2) was abolished by SR141716A in all areas, while SR144528 blocked up to 51.8% of the coupling to Gi/0-proteins evoked by CP55,940 restricted to the nucleus basalis magnocellularis. Together, these results demonstrate that there are increased microglia and decreased astrocyte immunoreactivities 1 week after a specific deletion of BFCNs, which projects to cortical areas, where the CB1 receptor coupling to Gi/0-proteins is upregulated. However, at the lesion site, the area with the highest neuroinflammatory response, there is also a limited contribution of CB2.

Neuroprotective effects of curcumin via autophagy induction in 6-hydroxydopamine Parkinson's models

Curcumin, a polyphenolic compound extracted from curcuma longa, acts as a nontoxic matter with anti-oxidant and anti-inflammatory effects as well as antiproliferative activities. Here, our research aimed to explore the neuroprotective effects of curcumin both in the 6-hydroxydopamine (6-OHDA)-lesioned rat model of Parkinson's disease (PD) in vivo and 6-OHDA-lesioned PC12 cells in vitro. In vitro, 6-OHDA caused a distinct decrease in cell viability of PC12 cells (150 μM). With the incubation of curcumin (1 μM), 6-OHDA-induced apoptosis was suppressed, increasing the autophagy markers (LC3-II/LC3-I, Beclin-1) and inhibiting phosphor-AKT/AKT, phosphor-mTOR/mTOR. In vivo, curcumin (50 mg/kg) reduced the accumulation of a-synuclein and led to higher parkinsonian disability scores in 6-OHDA-lesioned PD rats, contributing to induction of autophagy through inhibiting AKT/mTOR signal pathway. Moreover, treatment with autophagy inhibitors, such as 3-MA and chloroquine, abolished the neuroprotective effects of curcumin as evidence by compromised autophagy and declined motor behavior in PD rats. In conclusion, the present study demonstrated that curcumin repressed PC12 cell death in vitro and improved parkinsonian disability scores in vivo by inhibiting AKT/mTOR signaling pathway which mediated by autophagy, indicating a potential value of curcumin in the therapeutic intervention of Parkinson's disease.

Inescapable footshocks induce molecular changes in the prefrontal cortex of rats in an amyloid-beta-42 model of Alzheimer’s disease

Alzheimer's disease (AD) affects several brain areas, including the prefrontal cortex (PFC) involved in execution, working memory, and fear extinction. Despite these critical roles, the PFC is understudied in AD pathology. People with post-traumatic stress disorder (PTSD) have twice the risk of developing AD, and the underlying mechanisms linking these two diseases are less understood. Here, we investigated the effect of footshock stress on behavioural vis-a-vis molecular changes in the PFC of an amyloid-beta (Aβ)-42 lesion rat model of AD. Trauma-like conditions were induced by exposing the animals to several footshocks. AD-like condition was induced via intra-hippocampal injection of Aβ-42 peptide. Following Aβ-42 injections, animals were tested for behavioural changes using the Open Field Test (OFT) and Y-maze test. The PFC was later harvested for neurochemical analyses. Our results showed an interactive effect of footshocks and Aβ-42 lesion on: reduced percentage alternation in the Y-maze test, suggesting memory impairment; reduced number of line crosses and time spent in the centre square of the OFT, indicating anxiogenic responses. Similarly, there was an interactive effect of footshocks and Aβ-42 lesion on: increased FK506 binding protein 51 (FKBP5) expression, which can be associated with stress-induced anxiogenic behaviours; and increased neuronal apoptosis in the PFC of the animals. In addition, footshocks, as well as Aβ-42 lesion, reduced superoxide dismutase levels and Bridging Integrator-1 (BIN1) expression in the PFC of the animals, which can be linked to the observed memory impairment. In conclusion, our findings indicate that footshocks exaggerate PFC-associated behavioural and molecular changes induced by an AD-like pathology.

Cannabis Vapor Exposure Alters Neural Circuit Oscillatory Activity in a Neurodevelopmental Model of Schizophrenia: Exploring the Differential Impact of Cannabis Constituents.

Cannabis use is highly prevalent in patients with schizophrenia and worsens the course of the disorder. To understand how exposure to cannabis changes schizophrenia-related oscillatory disruptions, we investigated the impact of administering cannabis vapor containing either Δ9-tetrahydrocannabinol (THC) or balanced THC/cannabidiol (CBD) on oscillatory activity in the neonatal ventral hippocampal lesion (NVHL) rat model of schizophrenia. Male Sprague Dawley rats underwent lesion or sham surgeries on postnatal day 7. In adulthood, electrodes were implanted targeting the cingulate cortex (Cg), the prelimbic cortex (PrLC), the hippocampus (HIP), and the nucleus accumbens (NAc). Local field potential recordings were obtained after rats were administered either the “THC-only” cannabis vapor (8–18% THC/0% CBD) or the “Balanced THC:CBD” cannabis vapor (4–11% THC/8.5–15.5% CBD) in a cross-over design with a 2-week wash-out period between exposures. Compared to controls, NVHL rats had reduced baseline gamma power in the Cg, HIP, and NAc, and reduced HIP-Cg high-gamma coherence. THC-only vapor exposure broadly suppressed oscillatory power and coherence, even beyond the baseline reductions observed in NHVL rats. Balanced THC:CBD vapor, however, did not suppress oscillatory power and coherence, and in some instances enhanced power. For NVHL rats, THC-only vapor normalized the baseline HIP-Cg high-gamma coherence deficits. NHVL rats demonstrated a 20 ms delay in HIP theta to high-gamma phase coupling, which was not apparent in the PrLC and NAc after both exposures. In conclusion, cannabis vapor exposure has varying impacts on oscillatory activity in NVHL rats, and the relative composition of naturally occurring cannabinoids may contribute to this variability.

The Impact of Adolescent Alcohol Exposure on Nicotine Behavioral Sensitization in the Adult Male Neonatal Ventral Hippocampal Lesion Rat.

Nicotine and alcohol use is highly prevalent among patients with serious mental illness, including those with schizophrenia (SCZ), and this co-occurrence can lead to a worsening of medical and psychiatric morbidity. While the mechanistic drivers of co-occurring SCZ, nicotine use and alcohol use are unknown, emerging evidence suggests that the use of drugs during adolescence may increase the probability of developing psychiatric disorders. The current study used the neonatal ventral hippocampal lesion (NVHL) rat model of SCZ, which has previously been shown to have enhanced nicotine behavioral sensitization and, following adolescent alcohol, increased alcohol consumption. Given how commonly alcohol is used by adolescents that develop SCZ, we used the NVHL rat to determine how exposure to adolescent alcohol impacts the development of nicotine behavioral sensitization in adulthood. Male Sprague-Dawley rats underwent the NVHL surgery or a sham (control) surgery and subsequently, half of each group was allowed to drink alcohol during adolescence. Nicotine behavioral sensitization was assessed in adulthood with rats receiving subcutaneous injections of nicotine (0.5 mg/kg) each day for 3 weeks followed by a nicotine challenge session 2 weeks later. We demonstrate that all groups of rats became sensitized to nicotine and there were no NVHL-specific increases in nicotine behavioral sensitization. We also found that NVHL rats appeared to develop sensitization to the nicotine paired context and that adolescent alcohol exposure blocked this context sensitization. The current findings suggest that exposure to alcohol during adolescence can influence behaviors that manifest in the adult NVHL rat (i.e., context sensitization). Interestingly, nicotine behavioral sensitization levels were not altered in the NVHL groups regardless of adolescent alcohol exposure in contrast to prior reports.

Age-related biochemical dysfunction in 6-OHDA model rats subject to induced- endurance exercise

Exercise can alleviate the disorders considered as the normal consequences of aging. Whether or not the treadmill endurance training affects the biochemical markers in the Parkinson's disease model rats after the 6-hydroxydopamine (6-OHDA) injection is assessed in this article. The experimental groups of N=8 rats consist of 1) Saline and Young sedentary (S-Young); 2) Saline and Old sedentary (S-Old); 3) Young and 6-OHDA without exercise (Y); 4) Young and 6-OHDA with exercise (YE); 5) Old and 6-OHDA without exercise (O); and 6) Old and 6-OHDA with exercise (OE). An 8 μg of 6-OHDA is injected into the right MFB. The rotation due to apomorphine, weight variation, and some biochemical expression are measured in the rats’ striatum. Exposure to 6-OHDA: increase weight loss by (%8) and rotation by (%90), reduce the protein levels of Bdnf by (30%), Th by (43%), and Tfam by (24%), in aging rats (P<0.05). The P53 level rose after the injection compared with the same Saline group (Old rats: 27% and Young rats: 14%), the highest in the O group. The findings indicate that endurance exercise amends the mitochondrial parameters and the apomorphine-induced rotation impairments in the presence of 6-OHDA injection. These positive effects of treadmill running in unilateral 6-OHDA lesioned rat model are age-dependent and are more significant in younger rats.

Role of mononuclear stem cells and decellularized amniotic membrane in the treatment of skin wounds in rats

ABSTRACT Stem cells (SC) and amniotic membrane (AM) are recognized for their beneficial impacts on the healing of cutaneous wounds. Thus, this study evaluated the capacity of tissue repair in a skin lesion rat model. Forty Wistar rats were randomized into four groups: group I – control, with full-thickness lesions on the back, without SC or AM; group II–injected SC; group III – covered by AM; group IV–injected SC and covered by AM. Lesion closure was assessed using contraction rate (Cr). Histochemical and immunohistochemical analyses were performed, and collagen, elastic fibers, fibroblast differentiation factor (TGF-β), collagen remodeling (MMP-8), and the number of myofibroblasts and blood vessels (α-SMA) were evaluated. On the 7th postoperative day, Cr 1st-7th day levels were higher in groups III and IV. However, on the 28th day, Cr 1st-28th day were higher in the control group. Picrosirius staining showed that type I collagen was predominant in all groups; however, the SC + AM group obtained a higher average when compared to the control group. Elastic fiber analysis showed a predominance in groups that received treatment. Groups II and IV showed the lowest expression levels of TGF-β and MMP-8, and α-SMA was significantly lower in group IV. The application of SC and AM accelerated the initial healing phase, probably owing to their anti-inflammatory effect that favored early formation of collagen and elastic fibers.

L-3,4-Dihydroxyphenylalanine Recovers Circadian Rhythm Disturbances in the Rat Models of Parkinson's Disease by Regulating the D1R-ERK1/2-mTOR Pathway.

Objective: Patients with Parkinson's disease (PD) frequently experience disruptions in the 24-h daily profile of both behavioral and biological markers. However, whether L-3,4-dihydroxyphenylalanine (L-dopa) influences these markers associated with circadian rhythm or not is still an open question. This study aims to explore the L-dopa effects on the rhythmic expression of core clock proteins [brain and muscle Arnt-like protein-1 (BMAL1) and circadian locomotor cycle kaput (CLOCK)], in the striatum of the rat model of PD and its underlying molecular mechanisms.Methods: Unilateral 6-hydroxydopamine (6-OHDA)-lesioned rat models were used in this study. L-dopa administrations were adopted to investigate the changes of circadian rhythm in PD. The behavioral tests and the measurements of the blood pressure (BP) and temperature were evaluated. The striatum was collected at intervals of 4 h. Western blot was used to examine the expressions of clock protein and the molecular protein of the D1R-ERK1/2-mTOR pathway. The rhythmic expressions of symptom parameters and circadian proteins were analyzed using the Cosinor model and/or the coefficient of variability (CV) that was used to describe the variability of the 24-h rhythm.Results: The circadian rhythms of BP and temperature were disrupted in 6-OHDA-lesioned PD rats compared with the sham group, while this process was reversed mildly by L-dopa treatment. The expressions of BMAL1 and CLOCK protein were rhythmic fluctuated without significant phase alterations when 6-OHDA or L-dopa was applied. Furthermore, the expressions of striatal BMAL1 protein in the 6-OHDA-lesioned group were significantly lower than those in the sham group at 04:00, 08:00, and 12:00, and the CLOCK protein was decreased at 04:00, 08:00, 12:00, 16:00, and 20:00 (all p < 0.05). The CV of the expressions of both BMAL1 and CLOCK was decreased in the 6-OHDA group; this process was reversed by L-dopa. Moreover, the CV of BMAL1 and CLOCK was elevated in the L-dopa rats. The phosphorylation levels of ERK1/2, S6K1, and 4E-BP1 in 6-OHDA-lesioned striatum were increased by L-dopa or D1 receptor agonist SKF38393 (p < 0.05, respectively), not by the combination of L-dopa and D1 receptor antagonist SCH23390, which was similar to the expressions of BMAL1 and CLOCK.Conclusion: L-dopa recovers the circadian rhythm disturbances in PD rats by regulating the D1R-ERK1/2-mTOR pathway.