Differential regulation of TRP channels in a rat model of neuropathic pain

Neuropathic pain is a chronic disease resulting from dysfunction of the nervous system often due to peripheral nerve injury. Hypersensitivity to sensory Stimuli (mechanical, thermal or chemical) is a common source of pain in patients and ion channels involved in detecting these Stimuli are possible candidates for inducing and/or maintaining the pain. Transient receptor potential (TRP) channels expressed on nociceptors respond to different sensory stimuli and a few of them have been studied previously in the models of neuropathic pain. Using real-time PCR for quantification of all known TRP channels we identified several TRP channels, which have not been associated with nociception OF neuropathic pain before, to be expressed in the DRG and to be differentially regulated after spared nerve injury (SNI). Of all TRP channel members, TRPML3 showed the most dramatic change in animals exhibiting neuropathic pain behaviour compared to control animals. fit situ hybridisation showed a widespread increase of expression ill neurons of small, medium and large cell sizes, indicating expression ill multiple subtypes. Co-localisation of TRPML3 with CGRP, NF200 and IB4 staining confirmed a broad Subtype distribution. Expression studies during development showed that TRPML3 is all embryonic channel that is induced upon nerve injury in three different nerve injury models investigated. Thus. the current results link for the first time a re-expression of TRPML3 with the development of neuropathic pain conditions. In addition, decreased mRNA levels after SNI were seen for TRPM6, TRPM8, TRPV1, TRPA1, TRPC3, TRPC4 and TRPC5. (C) 2009 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Chelatable zinc modulates excitability and seizure duration in the amygdala rapid kindling model

Zinc is present in high concentration in many structures of the limbic circuitry, however the role of zinc as a neuromodulator in such synapses is stilt uncertain. In this work, we verified the effects of zinc chelation in an animal model of epileptogenesis induced by amygdala rapid kindling. The basolateral. amygdala was electrically stimulated ten times per day for 2 days. A single stimulus was applied on the third day. Stimulated animals received injections of PBS or the zinc chelator diethildythiocarbamate acid (DEDTC) before each stimulus series. Animals were monitored with video-EEG and were perfused 3 h after the last stimulus for subsequent neo-Timm and Ftuoro-Jade B analysis. Zinc chelation decreased the duration of both behavioral seizures and electrical after-discharges, and also decreased the EEG spikes frequency, without changing the progression of behavioral seizure severity. These results indicate that the zinc ion may have a facilitatory role during kindling progression. (c) 2008 Elsevier B.V. All rights reserved.

A general hazard model for lifetime data in the presence of cure rate

Historically, the cure rate model has been used for modeling time-to-event data within which a significant proportion of patients are assumed to be cured of illnesses, including breast cancer, non-Hodgkin lymphoma, leukemia, prostate cancer, melanoma, and head and neck cancer. Perhaps the most popular type of cure rate model is the mixture model introduced by Berkson and Gage [1]. In this model, it is assumed that a certain proportion of the patients are cured, in the sense that they do not present the event of interest during a long period of time and can found to be immune to the cause of failure under study. In this paper, we propose a general hazard model which accommodates comprehensive families of cure rate models as particular cases, including the model proposed by Berkson and Gage. The maximum-likelihood-estimation procedure is discussed. A simulation study analyzes the coverage probabilities of the asymptotic confidence intervals for the parameters. A real data set on children exposed to HIV by vertical transmission illustrates the methodology.

Effects of cannabidiol on amphetamine-induced oxidative stress generation in an animal model of mania

Cannabidiol (CBD), a Cannabis sativa constituent, may present a pharmacological profile similar to mood stabilizing drugs, in addition to anti-oxidative and neuroprotective properties. The present study aims to directly investigate the effects of CBD in an animal model of mania induced by D-amphetamine (D-AMPH). In the first model (reversal treatment), rats received saline or D-AMPH (2 mg/kg) once daily intraperitoneal (i.p.) for 14 days, and from the 8th to the 14th day, they were treated with saline or CBD (15, 30 or 60 mg/kg) i.p. twice a day. In the second model (prevention treatment), rats were pretreated with saline or CBD (15, 30, or 60 mg/kg) regime i.p. twice a day, and from the 8th to the 14th day, they also received saline or D-AMPH i.p. once daily. In the hippocampus CBD (15 mg/kg) reversed the D-AMPH-induced damage and increased (30 mg/kg) brain-derived neurotrophic factor (BDNF) expression. In the second experiment, CBD (30 or 60 mg/kg) prevented the D-AMPH-induced formation of carbonyl group in the prefrontal cortex. In the hippocampus and striatum the D-AMPH-induced damage was prevented by CBD (15, 30 or 60 mg/kg). At both treatments CBD did not present any effect against D-AMPH-induced hyperactivity. In conclusion, we could not observe effects on locomotion, but CBD protect against D-AMPH-induced oxidative protein damage and increased BDNF levels in the reversal model and these effects vary depending on the brain regions evaluated and doses of CBD administered.

Effects of beta-carboline harmine on behavioral and physiological parameters observed in the chronic mild stress model: Further evidence of antidepressant properties

The chronic mild stress (CMS) model has been used as an animal model of depression which induces anhedonic behavior in rodents. The present study was aimed to evaluate the behavioral and physiological effects of administration of P-carboline harmine in rats exposed to CMS Procedure. To this aim, after 40 days of exposure to CMS procedure, rats were treated with harmine (15 mg/kg/day) for 7 days. In this study, sweet food consumption, adrenal gland weight, adrenocorticotrophin hormone (ACTH) levels, and hippocampal brain-derived-neurotrophic factor (BDNF) protein levels were assessed. Our findings demonstrated that chronic stressful situations induced anhedonia, hypertrophy of adrenal gland weight, increase ACTH circulating levels in rats and increase BDNF protein levels. Interestingly, treatment with harmine reversed anhedonia, the increase of adrenal gland weight, normalized ACTH circulating levels and BDNF protein levels. Finally, these findings further support the hypothesis that harmine could be a new pharmacological tool for the treatment of depression. (C) 2009 Elsevier Inc. All rights reserved.

Histology of the regenerate and docking site in bone transport

Bone transport is based on the principle of distraction osteogenesis described by Ilizarov and is a consecrated method for the treatment of segmental bone defects. One of its most problematic and, paradoxically, least studied aspects is the consolidation of the docking site. We studied histologically the ossification of the docking site and regenerate to determine any difference between them. Nine adult sheep were submitted to correction of a 1-cm tibial diaphyseal defect using a system of plate-fixed bone transport, with latency period of 1 week and 0.2 mm distraction of the transported segment four times a day. The sheep were divided into three groups of three animals each, according to the observation period of 3, 6 or 12 weeks between the fixation of the transported fragment and the euthanasia. The docking site and the regenerate were studied histologically on sections stained with Masson trichrome. The main mode of docking site ossification was the endochondral one and although intramembranous ossification was also observed simultaneously, it was limited to rare and small foci. In contrast, intramembranous ossification played the major role in the regenerate, with bone formation evolving from the base segment to the target segment. The experimental bone transport model proposed in the present study permits us to conclude that there is a clear difference between the ossification of the docking site and of the regenerate.

The melatonin action on stromal stem cells within pericryptal area in colon cancer model under constant light

Constant light (LL) is associated with high incidence of colon cancer. MLT supplementation was related to the significant control of preneoplastic patterns. We sought to analyze preneoplastic patterns in colon tissue from animals exposed to LL environment (14 days; 300 lx), MLT-supplementation (10 mg/kg/day) and DMH-treatment (1,2 dimethylhydrazine; 125 mg/kg). Rodents were sacrificed and MLT serum levels were measured by radioimmunoassay. Our results indicated that LL induced ACF development (p < 0.001) with a great potential to increase the number of CD133(+) and CD68(+) cells (p < 0.05 and p < 0.001). LL also increased the proliferative process (PCNA-Li; p < 0.001) as well as decreased caspase-3 protein (p < 0.001), related to higher COX-2 protein expression (p < 0.001) within pericryptal colonic stroma (PCCS). However, MLT-supplementation controlled the development of dysplastic ACF (p < 0.001) diminishing preneoplastic patterns into PCCS as CD133 and CD68 (p < 0.05 and p < 0.001). These events were relative to decreased PCNA-Li index and higher expression of caspase-3 protein. Thus, MLT showed a great potential to control the preneoplastic patterns induced by LL. (C) 2011 Elsevier Inc. All rights reserved.

Neuronal maturation in an experimental model of brain tissue heterotopia in the lung

Neural maturation involves diverse interaction and signaling mechanisms that are essential to the development of the nervous system. However, little is known about the development of neurons in heterotopic brain tissue in the lung, a rare abnormality observed in malformed babies and fetuses. The aim of this study was to identify the neurons and to investigate their maturation in experimental brain tissue heterotopia during fetal and neonatal periods. The fetuses from 24 pregnant female Swiss mice were used to induce brain tissue heterotopia on the 15th gestational day. Briefly, the brain of one fetus of each dam was extracted, disaggregated, and injected into the right hemithorax of siblings. Six of these fetuses with pulmonary brain tissue implantation were collected on the 18th gestational day (group E18), and six others were collected on the 8th postnatal day (group P8). The brain of each fetus from dams not submitted to any experimental procedure was collected on the 18th gestational day (group CE18) and on the 8th postnatal day (group CP8) to serve as a control for neuronal quantitation and maturation. Immunohistochemical staining of NeuN was used to assess neuron quantity and maturation. The NeuN labeling index was greater in the postnatal period than in the fetal period for the experimental and control groups (138 > E18 and CP8 > CE18), although there were fewer neurons in experimental than in control groups (P8 < CP8 and El 8 < CE1 8) (P < 0.005). These results indicate that fetal neuroblasts/neurons not only survive a dramatic event such as mechanical disaggregation, in the same way as it happens in human cases, but also they retain their development in heterotopia, irrespective of local tissue influences.

Giardia duodenalis: Pathological alterations in gerbils, Meriones unguiculatus, infected with different dosages of trophozoites

To examine the infection kinetics and development of alterations in the small intestine of gerbils (Meriones unguiculatus), 72 gerbils were divided into six groups (A to F), with A serving as control and the others inoculated with increasing doses of trophozoites from Giardia duodenalis human isolate. The infection kinetics and the development of histopathological alterations were monitored by optical scanning electron microscopy (SEM). A 12-day prepatent period was observed, with intermittent elimination up to day 35 after inoculation. Statistically significant differences were found between the mean number of trophozoites recovered, per group, on the days of sacrifice, and a positive correlation between the moculum dosage and the number of trophozoites recovered. Morphometrically, the villus:crypt ratio showed a drop in all the groups when compared with the control group. SEM revealed an increase in mucus production in the inoculated animals and the presence of trophozoite clusters at the top and base of the villi. The dosage of trophozoite inoculum does not interfere in the ability for infection to occur or in the development of histopathological alterations generated by intestinal colonization. (c) 2007 Elsevier Inc. All rights reserved.

beta 1 Integrin and VEGF expression in an experimental model of brain tissue heterotopia in the lung

Integrins and vascular endothelial growth factor (VEGF) are crucially involved in interaction, proliferation, migration, and survival of the cells. However, there is no report in the literature about beta 1 integrin and VEGF expression in heterotopic brain tissue. The aim of this study was to assess beta 1 integrin and VEGF expression in experimental brain tissue heterotopia in the lung during both fetal and neonatal periods. Twenty-four pregnant female Swiss mice were used to induce brain tissue heterotopia on the 15th gestational day. Briefly, the brain of one fetus of each dam was extracted, disaggregated, and injected into the right hemithorax of siblings. Six of these fetuses with pulmonary brain tissue implantation were collected on the 18th gestational day (group E18) and six other on the eighth postnatal day (group P8). Immunohistochemistry of the fetal trunks showed implantation of glial fibrillary acidic protein- and neuronal nuclei-positive heterotopic brain tissue, which were also positive for beta 1 integrin and VEGF in both groups E18 and P8. These results indicate that brain tissue heterotopia during fetal and postnatal period is able to complete integration with the lung tissue as well as to induce vascular proliferation which are the necessary steps for a successful implantation.

An Experimental Model of Meningoencephalomyelitis by Rocio Flavivirus in Balb/C Mice: Inflammatory Response, Cytokine Production, and Histopathology

Rocio virus (ROCV) is a flavivirus, probably transmitted by Culex mosquitoes and maintained in nature as a zoonosis of wild birds. Rocio virus caused a human epidemic of severe encephalitis that lasted from 1973 to 1980 in the Ribeira valley, in the southeastern coast of Brazil. After this outbreak, serologic evidence of ROCV circulation has been reported and public health authorities are concerned about a return of ROCV outbreaks in Brazil. We show here a study on the pathogenesis and the physiopathology of ROCV disease in the central nervous system of a Balb/C young adult mice experimental model. The animals were intraperitoneally infected by ROCV and followed from 0 to 9 days after infection, when all of them died. Nervous tissue samples were collected from infected animals for immunohistochemistry and molecular biology analysis. We observed the virus in the central nervous system, the inflammatory changes induced by Th1 and Th2 cytokines, and the final irreversible damage of nervous tissues by neuronal degeneration and apoptosis. These findings can help to better understand the pathogenesis and physiopathology of the human meningoencephalomyelitis by ROCV and other flaviviruses.

Heart rate and arterial pressure variability in the experimental renovascular hypertension model in rats

This study was conducted in one kidney, one clip (1K1C) Goldblatt hypertensive rats to evaluate vascular and cardiac autonomic control using different approaches: 1) evaluation of the autonomic modulation of heart rate (HR) and systolic arterial pressure (SAP) by means of autoregressive power spectral analysis 2) assessment of the cardiac baroreflex sensitivity; and 3) double blockade with methylatropine and propranolol. The 1K1C group developed hypertension and tachycardia. The 1K1C group also presented reduction in variance as well as in LF (0.23 +/- 0.1 vs. 1.32 +/- 0.2 ms(2)) and HF (6.6 +/- 0.49 vs. 15.1 +/- 0.61 ms(2)) oscillations of pulse interval. Autoregressive spectral analysis of SAP showed that 1K1C rats had an increase in variance and LF band (13.3 +/- 2.7 vs. 7.4 +/- 1.01 mmHg(2)) in comparison with the sham group. The baroreflex gain was attenuated in the hypertensive 1K1C (- 1.83 +/- 0.05 bpm/mmHg) rats in comparison with normotensive sham (-3.23 +/- 0.06 bpm/MmHg) rats. The autonomic blockade caused an increase in the intrinsic HR and sympathetic predominance on the basal HR of 1K1C rats. Overall, these data indicate that the tachycardia observed in the 1K1C group may be attributed to intrinsic cardiac mechanisms (increased intrinsic heart rate) and to a shift in the sympathovagal balance towards cardiac sympathetic over-activity and vagal suppression associated to depressed baroreflex sensitivity. Finally, the increase in the LF components of SAP also suggests an increase in sympathetic activity to peripheral vessels. (c) 2008 Elsevier B.V. All rights reserved.