The demyelination and altered motor performance following electrolytic lesion in the ventrolateral white matter of spinal cord in male rats: Benefit of post-injury administration of estradiol

Introduction: Spinal cord injuries are accompanied with significant demyelination of axons and subsequent locomotor dysfunction. To identify the extent of damage following electrolytic lesion of ventrolateral white matter, essential area for initiation of locomotor activity, we assessed demyelination as well as alteration in motor performance. Moreover, the protective effect of estradiol as a candidate treatment for preservation of myelin and locomotor activity after injury was examined due to its antiapoptotic and anti-inflammatory activities. Methods: A unilateral electrolytic lesion positioned in the right ventrolateral funiculus (VLF) was applied following laminectomy at T8-T9. In the estradiol-treated injury group, animals received a pharmacological single dose of estradiol valerate (4 mg/kg) at 30min post injury. Locomotor function was assessed using rotarod and open field tasks during 4 weeks after injury. Results: Obtained results showed significant demyelination at the site of injury and caudal areas following lesion as well as altered motor performance. Post-spinal cord injury administration of estradiol enhanced white matter maintenance at the site of lesion, restored the level of myelin basic protein (MBP), decreased TUNEL positive cells and improved functional recovery. Conclusion: Taken together, these results indicate that demyelination after lesion in VLF may be a contributing factor to limited motor performance, and suggest that pharmacological doses of estradiol may have an early protective effect through sparing of white matter. © 2016, Iranian Society of Physiology and Pharmacology. All rights reserved

Role of Microglia and Astrocyte in Central Pain Syndrome Following Electrolytic Lesion at the Spinothalamic Tract in Rats

Central pain syndrome (CPS) is a debilitating state and one of the consequences of spinal cord injury in patients. Many pathophysiological aspects of CPS are not well documented. Spinal glia activation has been identified as a key factor in the sensory component of chronic pain. In this study, the role of glial subtypes in the process of CPS induced by unilateral electrolytic lesion of spinothalamic tract (STT) is investigated. Male rats received a laminectomy at T8–T9 and then unilateral electrolytic lesion centered on the STT. Thermal and mechanical thresholds as well as locomotor function were measured on days 0, 3, 7, 14, 21, and 28 post-injuries by tail flick, von Frey filament, and open field tests, respectively. To investigate the spinal glial activation following denervation in STT-lesioned groups, Iba1 and GFAP were detected by immunohistochemistry and Western blotting at the same time points. Data showed that STT lesion significantly decreased thermal pain at day 3 in comparison with sham groups. Significant bilateral allodynia appeared in hind paws at day 14 after spinal cord injury and continued to day 28 (P<0.05). Additionally, electrolytic spinal lesion attenuated locomotor function of injured animals after 7 days (P<0.05). In both histological assessments and Western blotting, Iba1 increased at days 3 and 7 while increased GFAP occurred from day 14 to 28 after lesion. It appears that microglial activation is important in the early stages of pain development and astrocytic activation occurs later. These events may lead to behavioral outcomes especially central neuropathic pain

Estradiol attenuates spinal cord injury-induced pain by suppressing microglial activation in thalamic VPL nuclei of rats.

In our previous study we showed that central pain syndrome (CPS) induced by electrolytic injury caused in the unilateral spinothalamic tract (STT) is a concomitant of glial alteration at the site of injury. Here, we investigated the activity of glial cells in thalamic ventral posterolateral nuclei (VPL) and their contribution to CPS. We also examined whether post-injury administration of a pharmacological dose of estradiol can attenuate CPS and associated molecular changes. Based on the results,in the ipsilateral VPL the microglial phenotype switched o hyperactive mode and Iba1 expression was increased significantly on days 21 and 28 post-injury. The same feature was observed in contralateral VPL on day 28 (P<.05). These changes were strongly correlated with the onset of CPS (r(2)=0.670). STT injury did not induce significant astroglial response in both ipsilateral and contralateral VPL. Estradiol attenuated bilateral mechanical hypersensitivity 14 days after STT lesion (P<.05). Estradiol also suppressed microglial activation in the VPL. Taken together, these findings indicate that selective STT lesion induces bilateral microglia activation in VPL which might contribute to mechanical hypersensitivity. Furthermore, a pharmacological dose of estradiol reduces central pain possibly via suppression of glial activity in VPL region

Urogenital chlamydia trachomatis treatment failure with azithromycin: A meta-analysis

Background: Chlamydia Trachomatis is one of the most common pathogens transmitted through the genital tract in humans that leads to urogenital infection. Objective: Given the high prevalence of chlamydia infection and its adverse effects on the health of women and men, the present meta-analysis was conducted to determine the rate of treatment failure with azithromycin. Materials and Methods: Databases including MEDLINE, ISI - Web of Science, PubMed, EMBASE, Scopus, ProQuest, and Science Direct were searched for articles published between 1991 and 2018. The quality of the selected articles was assessed using the Cochrane risk of bias assessment tool. Heterogeneity was determined using the I2 and Cochrane Q-Test. Subgroup analysis and meta-regression were used to compare the prevalence rates on different levels of the variables. Results: A total of 21 articles that met the inclusion criteria were ultimately assessed. The pooled estimate of azithromycin failure rate was 11.23% (CI 95%: 8.23%-14.24%). Also, the azithromycin failure rate was 15.87% (CI 95%: 10.20%-21.54%) for the treatment of urethritis, 7.41% (CI 95%: 0.60%-14.22%) for cervicitis, and 7.14% (CI 95%: 10.90%-3.39%) for genital chlamydia. The pooled estimate of failure rate difference was 2.37% (CI 95%: 0.68%-4.06%), which shows that azithromycin has a higher failure rate in the treatment of chlamydia compared to doxycycline and other examined medications. The meta-regression results showed that the patient’s age contributes significantly to the heterogeneity for azithromycin treatment failure rate (β = 0.826; p = 0.017). Conclusion: Azithromycin has a higher failure rate than doxycycline and other studied medications in treating urogenital chlamydia infections. Key words: Azithromycin, Chlamydia trachomatis, Urogenital, Treatment failure, Meta-analysis

Intra-arterial verapamil improves functional outcomes of thrombectomy in a preclinical model of extended hyperglycemic stroke

The abrupt hyperglycemic reperfusion following thrombectomy has been shown to harm the efficacy of the intervention in stroke patients with large vessel occlusion. Studies of ours and others have shown thioredoxin-interacting protein (TXNIP) is critically involved in hyperglycemic stroke injury. We recently found verapamil ameliorates cerebrovascular toxicity of tissue plasminogen activators in hyperglycemic stroke. The present study aims to answer if verapamil exerts direct neuroprotective effects and alleviates glucose toxicity following thrombectomy in a preclinical model of hyperglycemic stroke. Primary cortical neural (PCN) cultures were exposed to hyperglycemic reperfusion following oxygen-glucose deprivation (OGD), with or without verapamil treatment. In a mouse model of intraluminal stroke, animals were subjected to 4 h middle cerebral artery occlusion (MCAO) and intravenous glucose infusion. Glucose infusion lasted one more hour at reperfusion, along with intra-arterial (i.a.) verapamil infusion. Animals were subjected to sensorimotor function tests and histological analysis of microglial phenotype at 72 h post-stroke. According to our findings, glucose concentrations (2.5–20 mM) directly correlated with TXNIP expression in OGD-exposed PCN cultures. Verapamil (100 nM) effectively improved PCN cell neurite growth and reduced TXNIP expression as well as interaction with NOD-like receptor pyrin domain-containing-3 (NLRP3) inflammasome, as determined by immunoblotting and immunoprecipitation. In our mouse model of extended hyperglycemic MCAO, i.a. verapamil (0.5 mg/kg) could attenuate neurological deficits induced by hyperglycemic stroke. This was associated with reduced microglial pro-inflammatory transition. This finding encourages pertinent studies in hyperglycemic patients undergoing thrombectomy where the robust reperfusion may exacerbate glucose toxicity

Effect of WR-1065 on 6-hydroxydopamine-induced catalepsy and IL-6 level in rats

Objective(s): Neuroinflammation and oxidative stress play a key role in pathogenesis of Parkinson’s disease (PD). In the present study we investigated the effect of reactive oxygen species (ROS) scavenger WR-1065 on catalepsy and cerebrospinal fluid (CSF) level of interleukin 6(IL-6) and striatum superoxide dismutase (SOD) activity  in 6-hydroxydopamine (6-OHDA) induced experimental model of PD. Materials and Methods: Seventy two male Wistar rats were divided into 9 equal groups and 6-OHDA (8 μg/2 μl/rat) was infused unilaterally into substantia nigra pars copmacta (SNc) to induce PD. Catalepsy was measured by standard bar test, CSF level of IL-6 was assessed by enzyme-linked immunosorbent assay (ELISA) method and SOD activity measured by spectrophotometric method. In pre-treatment groups WR-1065 (20, 40 and 80 μg/2 μl/rat/day, for 3 days) was infused into the SNc before 6-OHDA administration and 21 days later, as a recovery period, behavioral and molecular assay tests were done. Results: Our results showed that pre-treatment with WR-1065 improved (

Subsensitivity to Opioids Is Receptor-Specific in Isolated Guinea Pig Ileum and Mouse Vas Deferens after Obstructive Cholestasis

ABSTRACT The rate and degree of subsensitivity development to morphine (-opioid receptor, preferred, but not selective agonist) and U50488H (highly selective -opioid receptor agonist) were assessed in vitro on guinea pig ileum (GPI) of cholestatic animals 2, 5, and 7 days after bile duct ligation. In addition to this phenomenon of morphine, the effects of U50488H and SNC 80 (highly selective ␦-opioid receptor agonist) were studied in vitro on mice vas deferens (MVD) of cholestatic animals 2, 5, 7, 10, and 15 days after bile duct ligation. The IC 50 for each compound was determined in these preparations. The ratio of the IC 50 in bile duct-ligated animals to sham and control animals provides a quantitative index for the degree of subsensitivity development to each agonist. For any given time, the highest degree of subsensitivity to morphine was observed in GPI of cholestatic animals, whereas in MVD obtained from the cholestatic animals, the highest degree of subsensitivity developed to inhibitory effect of SNC 80. The subsensitivity development in cholestatic animals was time dependent; in GPI the maximum subsensitivity developed after 7 days of the operation, whereas the maximum subsensitivity in MVD developed 15 days after bile duct ligation. Moreover, subsensitivity to exogenous acetylcholine and norepinephrine in GPI and MVD, respectively, did not develop in the presence of subsensitivity to opioids in cholestatic animals. Significant accumulation of endogenous opioids in plasma of cholestatic animals has been shown in several studies and this may account for a significant development of subsensitivity to inhibitory effects of opioid agonists

Image1_Intra-arterial verapamil improves functional outcomes of thrombectomy in a preclinical model of extended hyperglycemic stroke.PDF

The abrupt hyperglycemic reperfusion following thrombectomy has been shown to harm the efficacy of the intervention in stroke patients with large vessel occlusion. Studies of ours and others have shown thioredoxin-interacting protein (TXNIP) is critically involved in hyperglycemic stroke injury. We recently found verapamil ameliorates cerebrovascular toxicity of tissue plasminogen activators in hyperglycemic stroke. The present study aims to answer if verapamil exerts direct neuroprotective effects and alleviates glucose toxicity following thrombectomy in a preclinical model of hyperglycemic stroke. Primary cortical neural (PCN) cultures were exposed to hyperglycemic reperfusion following oxygen-glucose deprivation (OGD), with or without verapamil treatment. In a mouse model of intraluminal stroke, animals were subjected to 4 h middle cerebral artery occlusion (MCAO) and intravenous glucose infusion. Glucose infusion lasted one more hour at reperfusion, along with intra-arterial (i.a.) verapamil infusion. Animals were subjected to sensorimotor function tests and histological analysis of microglial phenotype at 72 h post-stroke. According to our findings, glucose concentrations (2.5–20 mM) directly correlated with TXNIP expression in OGD-exposed PCN cultures. Verapamil (100 nM) effectively improved PCN cell neurite growth and reduced TXNIP expression as well as interaction with NOD-like receptor pyrin domain-containing-3 (NLRP3) inflammasome, as determined by immunoblotting and immunoprecipitation. In our mouse model of extended hyperglycemic MCAO, i.a. verapamil (0.5 mg/kg) could attenuate neurological deficits induced by hyperglycemic stroke. This was associated with reduced microglial pro-inflammatory transition. This finding encourages pertinent studies in hyperglycemic patients undergoing thrombectomy where the robust reperfusion may exacerbate glucose toxicity.</p