Histologic Study of Perifascial Areolar Tissue Implanted in Rabbit Vocal Folds: An Experimental Study

Objectives: Perifascial areolar tissue (PAT) consists of loose areolar tissue with viscoelastic properties that are similar to those found in tissues in the superficial layer of the vocal fold. The aim of this study was to quantify the inflammatory process and the collagen content of the graft, as well as that of the host tissue, after placement of a strip of PAT into the rabbit vocal fold. Methods: Surgeries were performed on 30 rabbits. The grafts were implanted in pockets that were surgically created in the right vocal fold. The left vocal fold (control group) was subjected only to surgical manipulation. The animals were divided into 3 groups for evaluations at 15 days, 3 months, and 6 months, and their larynx tissues were subsequently reviewed by histology. Results: The grafts were characterized by disorganized and thick collagen bundles and were identified in all study groups. The collagen density stayed constant over time. There was an acute inflammatory response induced by the graft at 15 clays that did not exist in the specimens taken at 3 and 6 months. Deposition of collagen fibers in the lamina propria was observed starting at 15 days after the operation and was more intense in the experimental vocal fold than in the control vocal fold. Conclusions: Our findings indicated that PAT has a low tendency for promoting an inflammatory response. However, there was a loss of the original architecture of the graft tissue and a greater deposition of collagen in the implanted vocal folds than in the control group.

Passive Acquisition of Protective Antibodies Reactive with Bordetella pertussis in Newborns via Placental Transfer and Breast-feeding

Although acquisition of anti-pertussis antibodies by the newborn via placental transfer has been demonstrated, a subsequent recrudescence of pertussis infection is often observed, particularly in infants. The present study investigated the passive transfer of anti-pertussis IgG and IgA antibodies to term newborns and their ability to neutralize bacterial pathogenicity in an in vivo experimental model using mice intracerebrally challenged with viable Bordetella pertussis. Forty paired samples of maternal/umbilical cord sera and colostrum were obtained. Anti-pertussis antibodies were analysed by immunoenzymatic assay and by Immunoblotting. Antibody neutralizing ability was assessed through intracerebral B. pertussis challenges in mice. Anti-pertussis IgG titres were equivalent in both maternal and newborn sera (medians = 1:225 and 1:265), with a transfer rate of 118%. The colostrum samples had variable specific IgA titres (median = 1:74). The immunoblotting assays demonstrated identical recognition profiles of paired maternal and newborn serum pools but different bacterial recognition intensities by colostrum pools. In the animal model, significant differences were always observed when the serum and colostrum samples and pools were compared with the positive control (P < 0.05). Unlike samples with lower anti-pertussis titres, samples with high titres showed protective capacities above 50%. Pertussis-absorbed serum and colostrum pools protected 30% of mice and purified IgG antibodies protected 65%. Both pooled and single-sample protective abilities were correlated with antibody titres (P < 0.01). Our data demonstrated the effectiveness of anti-pertussis antibodies in bacterial pathogenesis neutralization, emphasizing the importance of placental transfer and breast-feeding in protecting infants against respiratory infections caused by Bordetella pertussis.

In vitro fertilization, embryo development, and cell lineage segregation after pre- and/or postnatal exposure of female mice to ambient fine particulate matter

Objective: To evaluate effects of pre- and/or postnatal exposure to ambient fine particulate matter on fertilization, embryo development, and cell lineage segregation in preimplantation blastocysts using the IVF mouse model. Design: Animal model. Setting: Academic institution. Animal(S): Six-week-old, superovulated mice. Intervention(s): Pre- and postnatal exposure to filtered air (FA-FA), filtered-ambient air (FA-AA), or ambient air (AA-AA) in exposure chambers 24 hours a day for 9 weeks. Main Outcome Measure(S): Gestation length, litter size, sex ratio, ovarian response to superovulation, fertilization rate, embryo development, blastocyst and hatching rates, total cell count, and proportion of cell allocation to inner-cell mass (ICM) and trophectoderm (TE). Result(S): Gestation length, litter size and birth weight, live-birth index, and sex ratio were similar among exposure groups. Ovarian response was not affected by the exposure protocol. A multivariate effect for pre- and/or postnatal exposure to ambient fine particulate matter on IVF, embryo development, and blastocyst differential staining was found. Cell counts in ICM and ICM/TE ratios in blastocysts produced in the FA-FA protocol were significantly higher than in blastocysts produced in the FA-AA and AA-AA protocols. No difference in total cell count was observed among groups. Conclusion(S): Our study suggests that exposure to ambient fine particulate matter may negatively affect female reproductive health by disrupting the lineage specification at the blastocyst stage without interfering in early development of the mouse embryo. (Fertil Steril (R) 2009;92:1725-35. (C) 2009 by American Society for Reproductive Medicine.)

Association Between Polymorphisms in GRIK2 Gene and Obsessive-Compulsive Disorder: A Family-Based Study

Several studies support a genetic influence on obsessive-compulsive disorder (OCD) etiology. The role of glutamate as an important neurotransmitter affecting OCD pathophysiology has been supported by neuroimaging, animal model, medication, and initial candidate gene studies. Genes involved in glutamatergic pathways, such as the glutamate receptor, ionotropic, kainate 2 (GRIK2), have been associated with OCD in previous studies. This study examines GRIK2 as a candidate gene for OCD susceptibility in a family-based approach. Probands had full DSM-IV diagnostic criteria for OCD. Forty-seven OCD probands and their parents were recruited from tertiary care OCD specialty clinics from France and USA. Genotypes of single nucleotide polymorphism (SNP) markers and related haplotypes were analyzed using Haploview and FBAT software. The polymorphism at rs1556995 (P = 0.0027; permuted P-value = 0.03) was significantly associated with the presence of OCD. Also, the two marker haplotype rs1556995/rs1417182, was significantly associated with OCD (P = 0.0019, permuted P-value = 0.01). This study supports previously reported findings of association between proximal GRIK2 SNPs and OCD in a comprehensive evaluation of the gene. Further study with independent samples and larger sample sizes is required.

Apoptosis, cell proliferation and modulation of cyclin-dependent kinase inhibitor p21(cip1) in vascular remodelling during vein arterialization in the rat

Neo-intima development and atherosclerosis limit long-term vein graft use for revascularization of ischaemic tissues. Using a rat model, which is technically less challenging than smaller rodents, we provide evidence that the temporal morphological, cellular, and key molecular events during vein arterialization resemble the human vein graft adaptation. Right jugular vein was surgically connected to carotid artery and observed up to 90 days. Morphometry demonstrated gradual thickening of the medial layer and important formation of neo-intima with deposition of smooth muscle cells (SMC) in the subendothelial layer from day 7 onwards. Transmission electron microscopy showed that SMCs switch from the contractile to synthetic phenotype on day 3 and new elastic lamellae formation occurs from day 7 onwards. Apoptosis markedly increased on day 1, while alpha-actin immunostaining for SMC almost disappeared by day 3. On day 7, cell proliferation reached the highest level and cellular density gradually increased until day 90. The relative magnitude of cellular changes was higher in the intima vs. the media layer (100 vs. 2 times respectively). Cyclin-dependent kinase inhibitors (CDKIs) p27(Kip1) and p16(INKA) remained unchanged, whereas p21(Cip1) was gradually downregulated, reaching the lowest levels by day 7 until day 90. Taken together, these data indicate for the first time that p21(Cip1) is the main CDKI protein modulated during the arterialization process the rat model of vein arterialization that may be useful to identify and validate new targets and interventions to improve the long-term patency of vein grafts.

The Ideal Timing for Experimental Cleft Lip Creation

Cleft lip and palate (CLP) is the most common congenital defect of the face. Many animal models have been utilized to study embryogenesis and pathogenesis of CLP, including the development of secondary anomalies and consequent deformities. However, the ideal gestational age for surgical creation of lip or palate defects in rat models has never been determined. The aim of the present study is to improve the experimental model utilizing rat fetuses, defining the most appropriate timing for creation of the lip defect model. The study was composed of three groups of fetuses undergoing surgical creation of a lip defect at the left side of the superior lip at 17.5, 18.5, and 19.5 days of gestation. Fetuses were harvested at 21.5 days of gestation (term = 22 days) and underwent macroscopic and microscopic analyses. We found that the most appropriate moment for lip defect creation was at 19.5 days, given the presence of lip depression at the site of the defect and asymmetry and retraction associated with interruption of the lip and complete reepithelialization of the borders of the defect.

Morphometry of saphenous nerve in young rats

The rat saphenous nerve contains only somato-sensory fibers and is used in investigations of neuropathic pain and its treatment. Due to its superficial anatomical path, the saphenous nerve is also widely used in electrophysiological studies. Nevertheless, morphologic and morphometric descriptions of the normal saphenous nerve are scanty in the literature and information on useful morphometric parameters of this nerve is still missing. Thus, the present study aimed to investigate the longitudinal and lateral symmetry of the saphenous nerve in young rats. Proximal and distal segments of the left and right saphenous nerves from female Wistar rats, aged 30 days (N = 5) were morphometrically evaluated and comparisons were made between sides and segments. Our results show that the saphenous nerve is longitudinally and laterally symmetric since there were no morphometric differences between proximal and distal segments, as well as between right and left sides. This lateral symmetry is important in order to validate those experiments in which the contralateral nerve is used as the control. Also, the longitudinal symmetry information is fundamental to further studies involving the ""dying back"" neuropathy models. The present study adds to the literature new morphometric information on the rat saphenous nerve that might be useful for a better interpretation of further studies involving this nerve and experimental models of nerve diseases. (c) 2007 Elsevier B.V. All rights reserved.

Protective Effect of RC-3095, an Antagonist of the Gastrin-Releasing Peptide Receptor, in Experimental Arthritis

Objective. To evaluate the antiinflammatory effects of RC-3095 in 2 experimental models of arthritis, collagen-induced arthritis (CIA) and antigen-induced arthritis (AIA), and to determine the mechanisms of action involved. Methods. RC-3095 was administered daily to mice with CIA and mice with AIA, after induction of disease with methylated bovine serum albumin. Disease incidence and severity were assessed using a clinical index and evaluation of histologic features, respectively. In mice with CIA, gastrin-releasing peptide receptor (GRPR) was detected by immunohistochemical analysis, while in mice with AIA, migration of neutrophils, presence of glycosaminoglycans, and lymphocyte proliferation, determined using the MTT assay, were assessed. Expression of cytokines interleukin-17 (IL-17), IL-1 beta, and tumor necrosis factor alpha (TNF alpha) was evaluated in all mouse knees using enzyme-linked immunosorbent assay. Treg cell production was assessed by flow cytometry in the joints of mice with AIA. Results. In mice with AIA, administration of RC-3095 reduced neutrophil migration, mechanical hypernociception, and proteoglycan loss. These findings were associated with inhibition of the levels of all 3 proinflammatory cytokines, decreased lymphocyte proliferation, and increased Treg cell numbers. In the CIA model, treatment with RC-3095 led to a significant reduction in arthritis clinical scores and the severity of disease determined histologically. Synovial inflammation, synovial hyperplasia, pannus formation, and extensive erosive changes were all dramatically reduced in the arthritic mice treated with RC-3095. Furthermore, arthritic mice treated with RC-3095 showed a significant reduction in the concentrations of IL-17, IL-1 beta, and TNF alpha, and showed a diminished expression of GRPR. Conclusion. These findings suggest that the GRP pathway has a significant role in chronic arthritis, and its inhibition can be explored as a possible therapeutic strategy in rheumatoid arthritis.

Stimulation of 5-HT1A or 5-HT2A receptors in the ventrolateral periaqueductal gray causes anxiolytic-, but not panicolytic-like effect in rats

Evidences from studies using electrical or chemical stimulation of the midbrain periaqueductal gray (PAG) suggest that whereas the dorsal PAG is critical for the regulation of panic-related defensive behaviors, the ventrolateral PAG (vlPAG) modulates generalized anxiety-related responses. In the present study we evaluated whether the activation of 5-HT1A and 5-HT2A/2C receptors in the ventrolateral column of the periaqueductal gray (vlPAG) causes differential effects on an anxiety- and a panic-related defensive behavior, respectively, inhibitory avoidance and escape, in male Wistar rats submitted to the elevated T-maze. Our results showed that intra-vlPAG injection of the endogenous agonist serotonin, the 5-HT1A/7 agonist 8-OH-DPAT or 5-HT2A/2C agonist DOI impaired the acquisition of inhibitory avoidance, without interfering with escape performance. The same selective anxiolytic effect was also observed after local administration of the benzodiazepine receptor agonist midazolam. Moreover, as shown by the results of antagonism studies, 5-HT2A receptors are recruited for the anxiolysis caused by serotonin and DOI. while 5-HT1A receptors account for the effect of 8-OH-DPAT. In conclusion, our data show that the activation of 5-HT1A and 5-HT2A receptors in the vlPAG affects defensive responses related to generalized anxiety, but not panic disorder. (C) 2008 Elsevier B.V. All rights reserved.

Involvement of median raphe nucleus 5-HT1A receptors in the regulation of generalized anxiety-related defensive behaviours in rats

Changes in 5-HT1A receptor-mediated neurotransmission at the level of the median raphe nucleus (MRN) are reported to affect the expression of defensive responses that are associated with generalized anxiety disorder (e.g. inhibitory avoidance) but not with panic (e.g. escape). The objective of this study was to further explore the involvement of MRN 5-HT1A receptors in the regulation of generalized anxiety-related behaviours. Results of experiment 1 showed that intra-MRN injection of the 5-HT1A/7 receptor agonist 8-OH-DPAT (0.6 nmol) in male Wistar rats impaired the acquisition of inhibitory avoidance, without interfering with the performance of escape in the elevated T-maze test of anxiety. Pre-treatment with the 5-HT1A receptor antagonist WAY-100635 (0.18 nmol) fully blocked this anxiolytic-like effect. As revealed by experiment 2, intra-MRN injection of 8-OH-DPAT (0.6, 3 or 15 nmol) also caused anxiolytic effect in rats submitted to the light-dark transition test, another animal model that has been associated with generalized anxiety. In the same test, intra-MRN injection of WAY-100635 (0.18, 0.37 or 0.74 nmol) caused the opposite effect. Overall, the current findings support the view that MRN 5-HT neurons, through the regulation of 5-HT1A somatodendritic autoreceptors, are implicated in the regulation of generalized anxiety-associated behaviours. (C) 2008 Elsevier Ireland Ltd. All rights reserved.

Involvement of the lateral habenula in the regulation of generalized anxiety- and panic-related defensive responses in rats

Recently obtained evidence points to the involvement of the lateral habenular nuclei (LHb) in the mediation of coping defensive responses to threatening/stressful stimuli. Nevertheless, the role of this brain area in the regulation of defensive responses that have been associated with specific subtypes of anxiety disorders recognized in clinical settings is presently unknown. To address this question, we investigated the effects of either electrolytic lesions or chemical stimulation of the LHb on the defensive behaviors generated in rats by the elevated T-maze. This experimental model allows the measurement, in a same rat, of two defensive behaviors, inhibitory avoidance and escape, that have been related in terms of psychopathology to generalized anxiety and panic disorders, respectively. Bilateral electrolytic lesions of the LHb (1 mA, 10 s) impaired inhibitory avoidance acquisition and facilitated escape performance. On the other hand, chemical stimulation of the LHb by bilateral microinjection of kainic acid (30-60 pmol/0.2 mu L) had the opposite effect, i.e., facilitated inhibitory avoidance and impaired escape. The present results indicate that the LHb exerts an opposed regulatory control on generalized anxiety- and panic-related defensive responses in rats. (c) 2008 Elsevier Inc. All rights reserved.

The anxiolytic-like effects of cannabidiol injected into the bed nucleus of the stria terminalis are mediated by 5-HT1A receptors

Cannabidiol (CBD) is a non-psychotomimetic compound from Cannabis sativa that induces anxiolytic-like effects in rodents and humans after systemic administration. Previous results from our group showed that CBD injection into the bed nucleus of the stria terminalis (BNST) attenuates conditioned aversive responses. The aim of this study was to further investigate the role of this region on the anxiolytic effects of the CBD. Moreover, considering that CBD can activate 5-HT1A receptors, we also verified a possible involvement of these receptors in those effects. Male Wistar rats received injections of CBD (15, 30, or 60 nmol) into the BNST and were exposed to the elevated plus-maze (EPM) or to the Vogel conflict test (VCT), two widely used animal models of anxiety. CBD increased open arms exploration in the EPM as well as the number of punished licks in the VCT, suggesting an anxiolytic-like effect. The drug did not change the number of entries into the enclosed arms of the EPM nor interfered with water consumption or nociceptive threshold, discarding potential confounding factors in the two tests. Moreover, pretreatment with the 5-HT1A receptor antagonist WAY100635 (0.37 nmol) blocked the effects of CBD in both models. These results give further support to the proposal that BNST is involved in the anxiolytic-like effects of CBD observed after systemic administration, probably by facilitating local 5-HT1A receptor-mediated neurotransmission.

Acute reversible inactivation of the ventral medial prefrontal cortex induces antidepressant-like effects in rats

The ventral medial prefrontal cortex (vMPFC) has direct connections to subcortical, diencephalic and brainstem structures that have been closely related to depression. However, studies aimed at investigating the role of the vMPFC in the neurobiology of depression have produced contradictory results. Moreover, the precise involvement of vMPFC anatomic subdivisions, the prelimbic(PL) and the infralimbic (IL) cortices, in regulating depressive-like behavior have been poorly investigated. The forced swimming test (FST) is a widely employed animal model aimed at detecting antidepressant-like effects. Therefore, to further investigate a possible involvement of the vMFPC in depressive-like behavior, rats bilaterally implanted with cannulae aimed at the PL or IL prefrontal cortices were submitted to 15 min of forced swimming (pre-test) followed, 24 h later, by a 5-min swimming session (test), where immobility time was registered. Synaptic transmission in these regions was temporarily inhibited using local microinjection of cobalt chloride at different periods of the experimental procedure (before or after the pre-test or before the test). PL inactivation decreased immobility time independently of the time of the injection. In the IL inactivation induced a significant antidepressant-like effect when performed immediately before the pre-test or before the test, but not after the pre-test. These results suggest that activation of the vMPFC is important for the behavioral changes observed in rats submitted to the FST. They further indicate that, although both the PL and IL cortices are involved in these effects, they may play different roles. (C) 2010 Elsevier B.V. All rights reserved.

Intra-dorsal periaqueductal gray administration of cannabidiol blocks panic-like response by activating 5-HT1A receptors

Activation of 5-HT1A receptors in the dorsal periaqueductal gray (dPAG) impairs escape behavior, suggesting a panicolytic-like effect. Cannabidiol (CBD), a major non-psychotomimetic compound present in Cannabis sativa, causes anxiolytic-like effects after intra-dPAG microinjections by activating 5-HT1A receptors. In the present work we tested the hypothesis that CBD could also impair escape responses evoked by two proposed animal models of panic: the elevated T-maze (ETM) and electric stimulation of dPAG. In experiment 1 male Wistar rats with a single cannula implanted in the dPAG received a microinjection of CBD or vehicle and, 10 min later, were submitted to the ETM and open field tests. In experiment 2 escape electrical threshold was measured in rats with chemitrodes implanted in the dPAG before and 10 min after CBD microinjection. In experiment 3 similar to experiment 2 except that the animals received a previous intra-dPAG administration of WAY-100635, a 5-HT1A receptor antagonist, before CBD treatment. In the ETM microinjection of CBD into the dPAG impaired inhibitory avoidance acquisition, an anxiolytic-like effect, and inhibited escape response, a panicolytic-like effect. The drug also increased escape electrical threshold, an effect that was prevented by WAY-100635. Together, the results suggest that CBD causes panicolytic effects in the dPAG by activating 5-HT1A receptors. (C) 2010 Elsevier B.V. All rights reserved.

The lateral habenula regulates defensive behaviors through changes in 5-HT-mediated neurotransmission in the dorsal periaqueductal gray matter

Chemical stimulation of the lateral nucleus of the habenula (LHb), an area implicated in the regulation of serotonergic activity in raphe nuclei, affects the acquisition of inhibitory avoidance and escape expression of rats submitted to the elevated T-maze test of anxiety. Here, we investigated whether facilitation of 5-HT-mediated neurotransmission in the dorsal periaqueductal gray (dPAG) accounts for the behavioral consequences in the elevated T-maze induced by chemical stimulation of the LHb. The dPAG in the midbrain, which is innervated by 5-HT fibers originating from the dorsal raphe nucleus (DRN), has been consistently implicated in the genesis/regulation of anxiety- and fear-related defensive responses. The results showed that intra-dPAG injection of WAY-100635 or ketanserin, 5-HT(1A) and 5-HT(2A/2C) receptor antagonists, respectively, counteracted the anti-escape effect caused by bilateral intra-LHb injection of kainic acid (60 pmol/0.2 mu l). Ketanserin, but not WAY-100635, blocked kainic acid`s facilitatory effect on inhibitory avoidance acquisition. Overall, the results suggest that the pathway connecting the LHb to the DRN is involved in the control of 5-HT release in the dPAG, and facilitation of 5-HT-mediated neurotransmission in the latter area distinctively impacts upon the expression of anxiety- and fear-related defensive behaviors. While stimulation of 5-HT(1A) receptors selectively affects escape performance, 5-HT(2A/2C) receptors modulate both inhibitory avoidance and escape. (C) 2010 Elsevier Ireland Ltd. All rights reserved.