Effect of different cryosurgical protocols using liquid nitrogen on bone tissue: a histomorphological analyze

The aim of the present experimental study was to evaluate the morphological effects of different liquid nitrogen cryosurgery protocols on bone tissue. The femoral diaphyses of 42 Wistar rats were exposed to three local and sequential applications of liquid nitrogen for 1 or 2 min, intercalated with periods of 5 min of passive thawing. The animals were sacrificed after 1, 2, 4 and 12 weeks and the specimens obtained were processed and analyzed histomorphologically. Histologically, an increase in bone necrosis was observed for the two protocols in the second week after cryotherapy. A significant osteogenic phase was observed after 4 weeks. Moreover, complete remodeling process was encountered at the end of the morphological observation period (12 weeks), especially on oneminute protocol. Thus, this study indicated that the 2-min protocol produced more marked bone necrosis than the 1-min protocol. In addition, the second experimental week was critical for bone necrosis with either cryotherapy protocol. Further studies are important for the understanding of the long-term behavior of bone tissue after cryoapplication of liquid nitroge

Experimental Model of Zymosan-Induced Arthritis in the Rat Temporomandibular Joint: Role of Nitric Oxide and Neutrophils

Aims. To establish a new model of zymosan-induced temporomandibular joint (TMJ) arthritis in the rat and to investigate the role of nitric oxide. Methods. Inflammation was induced by an intra-articular injection of zymosan into the left TMJ. Mechanical hypernociception, cell influx, vascular permeability, myeloperoxidase activity, nitrite levels, and histological changes were measured in TMJ lavages or tissues at selected time points. These parameters were also evaluated after treatment with the nitric oxide synthase (NOS) inhibitors L-NAME or 1400 W. Results. Zymosan-induced TMJ arthritis caused a time-dependent leucocyte migration, plasma extravasation, mechanical hypernociception, and neutrophil accumulation between 4 and 24 h. TMJ immunohistochemical analyses showed increased inducible NOS expression. Treatment with L-NAME or 1400 W inhibited these parameters. Conclusion. Zymosan-induced TMJ arthritis is a reproducible model that may be used to assess both the mechanisms underlying TMJ inflammation and the potential tools for therapies. Nitric oxide may participate in the inflammatory temporomandibular dysfunction mechanisms

Distortion-product otoacoustic emissions and auditory brainstem responses sensitivity assessment in cisplatin-induced ototoxicity in rats

SummaryCisplatin (cis-diamminedicloroplatinum) is an antineoplastic drug used in the treatment of a variety of cancers, especially head-and-neck cancer. Its ototoxicity, however, has been noted as a common side-effect which limits its use and causes significant morbidity.Aimto assess distortion-product otoacoustic emissions (DPOAE) and brainstem evoked response audiometry (BERA) sensitivity to detect secondary ototoxicity caused by different doses and means of administration of cisplatin in rats.Study DesignExperimental.Materials and MethodsMale Wistar rats were intraperitoneally (i.p.) injected with 24 mg/kg cisplatin, divided into three equal doses (8mg/kg) or a single i.p. injection of 16 mg/kg. The animals were evaluated by distortion product otoacoustic emission (DPOAE) or brainstem evoked response audiometry (BERA) on the 3rd and 4th days after the cisplatin injection.ResultsTreatment with cisplatin 24 mg/kg resulted in significant DPOAE decrease and it raised the BERA electrophysiological threshold. The 16mg/kg dose could not significantly reduce the DPOAE amplitude, but it raised the animals' hearing thresholds – detected by the BERA.ConclusionIn rats, BERA was more sensitivity than DPOAE at detecting cisplatin-induced ototoxicity in rats considering different doses and means of administration

Anti-inflammatory effects and possible mechanism of action of lupeol acetate isolated from Himatanthus drasticus (Mart.) Plumel

<p>Abstract</p> <p>Background</p> <p>The species <it>Himatanthus drasticus </it>is popularly known in Northeast Brazil as "janaguba" and belongs to the family Apocynaceae. The latex collected from its stem bark is used for several purposes including anti-inflammatory properties and presents among its bioactive constituents the pentacyclic triterpene lupeol. The objective of the present work was to study <it>in vivo </it>and <it>in vitro </it>the lupeol acetate (LA) isolated from the plant latex, in several models of inflammation.</p> <p>Methods</p> <p>Male Swiss mice (25-30 g, 6-24 animals per group) were administered with LA, 30 min before the test initiation. In the evaluation of analgesic activity the formalin test was used. The anti-inflammatory activity was evaluated by the following tests: paw edema induced by carrageenan and dextran, and the carrageenan-induced neutrophil migration into peritoneal cavities. Furthermore, the effect of LA on the myeloperoxidase release (MPO, an inflammation biomarker) from human neutrophils was also determined, as well as its antioxidant potential by the DPPH assay.</p> <p>Results</p> <p>In the formalin test, LA (10, 25 and 50 mg/kg, i.p.) inhibited both the 1^st(neurogenic, 0-5 min) and mainly the 2^nd(inflammatory, 20-25 min) phase. Naloxone completely reversed the LA effect, indicating the participation of the opioid system. LA also significantly inhibited carrageenan- and dextran-induced paw edemas, as well as the neutrophil migration to the peritoneal cavity evaluated by the carrageenan-induced pleurisia. In this model, the effect of a very low dose of LA (0.1 mg/kg) was potentiated by the same dose of pentoxifylline (PTX), a known TNF-alpha inhibitor. LA (25 and 50 μg/ml) was also very effective in inhibiting MPO released from stimulated human neutrophils, and significantly decreased the number of cells expressing iNOS activity in the paw of mice submitted to carrageenan-induced edema, suggesting a drug involvement with the NO system.</p> <p>Conclusions</p> <p>The anti-inflammatory effect of LA probably involves the opioid system, as indicated by the complete blockade of the opioid antagonist naloxone. Furthermore, the LA effect was potentiated by PTX (a TNF-alpha inhibitor). LA also decreased the number of iNOS cells, suggesting the participation of pro-inflammatory cytokines and the NO system in the drug action.</p

Effects of metformin on inflammation, oxidative stress, and bone loss in a rat model of periodontitis.

AimTo evaluate the effects of metformin (Met) on inflammation, oxidative stress, and bone loss in a rat model of ligature-induced periodontitis.Materials &amp; methodsMale albino Wistar rats were divided randomly into five groups of twenty-one rats each, and given the following treatments for 10 days: (1) no ligature + water, (2) ligature + water, (3) ligature + 50 mg/kg Met, (4) ligature + 100 mg/kg Met, and (5) ligature + 200 mg/kg Met. Water or Met was administered orally. Maxillae were fixed and scanned using Micro-computed Tomography (μCT) to quantitate linear and bone volume/tissue volume (BV/TV) volumetric bone loss. Histopathological characteristics were assessed through immunohistochemical staining for MMP-9, COX-2, the RANKL/RANK/OPG pathway, SOD-1, and GPx-1. Additionally, confocal microscopy was used to analyze osteocalcin fluorescence. UV-VIS analysis was used to examine the levels of malondialdehyde, glutathione, IL-1β and TNF-α from gingival tissues. Quantitative RT-PCR reaction was used to gene expression of AMPK, NF-κB (p65), and Hmgb1 from gingival tissues. Significance among groups were analysed using a one-way ANOVA. A p-value of p&lt;0.05 indicated a significant difference.ResultsTreatment with 50 mg/kg Met significantly reduced concentrations of malondialdehyde, IL-1β, and TNF-α (p &lt; 0.05). Additionally, weak staining was observed for COX-2, MMP-9, RANK, RANKL, SOD-1, and GPx-1 after 50 mg/kg Met. OPG and Osteocalcin showed strong staining in the same group. Radiographically, linear measurements showed a statistically significant reduction in bone loss after 50 mg/kg Met compared to the ligature and Met 200 mg/kg groups. The same pattern was observed volumetrically in BV/TV and decreased osteoclast number (p&lt;0.05). RT-PCR showed increased AMPK expression and decreased expression of NF-κB (p65) and HMGB1 after 50 mg/kg Met.ConclusionsMetformin, at a concentration of 50 mg/kg, decreases the inflammatory response, oxidative stress and bone loss in ligature-induced periodontitis in rats

Gliclazide reduced oxidative stress, inflammation, and bone loss in an experimental periodontal disease model

Objective: The aim of this study was to evaluate the effects of gliclazide on oxidative stress, inflammation, and bone loss in an experimental periodontal disease model. Material and Methods: Male albino Wistar rats were divided into no ligature, ligature, and ligature with 1, 5, and 10 mg/kg gliclazide groups. Maxillae were fixed and scanned using micro-computed tomography to quantify linear and bone volume/tissue volume (BV/TV) and volumetric bone loss. Histopathological, immunohistochemical and immunofluorescence analyses were conducted to examine matrix metalloproteinase-2 (MMP-2), cyclooxygenase 2 (COX-2), cathepsin K, members of the receptor activator of the nuclear factor kappa-Β ligand (RANKL), receptor activator of nuclear factor kappa-Β (RANK), osteoprotegerin (OPG) pathway, macrophage migration inhibitory factor (MIF), superoxide dismutase-1 (SOD-1), glutathione peroxidase-1 (GPx-1), NFKB p 50 (Cytoplasm), NFKB p50 NLS (nuclear localization signal), PI3 kinase and AKT staining. Myeloperoxidase activity, malondialdehyde and glutathione levels, while interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) levels were evaluated by spectroscopic ultraviolet-visible analysis. A quantitative reverse transcription polymerase chain reaction was used to quantify the gene expression of the nuclear factor kappa B p50 subunit (NF-κB p50), phosphoinositide 3-kinase (PI3k), protein kinase B (AKT), and F4/80. Results: Micro-computed tomography showed that the 1 mg/kg gliclazide treatment reduced linear bone loss compared to the ligature, 5 mg/kg gliclazide, and 10 mg/kg gliclazide treatments. All concentrations of gliclazide increased bone volume/tissue volume (BV/TV) compared to the ligature group. Treatment with 1 mg/kg gliclazide reduced myeloperoxidase activity, malondialdehyde, IL-1β, and TNF-α levels (p≤0.05), and resulted in weak staining for COX-2, cathepsin k, MMP-2, RANK, RANKL, SOD-1, GPx-1,MIF and PI3k. In addition, down-regulation of NF-κB p50, PI3k, AKT, and F4/80 were observed, and OPG staining was strong after the 1 mg/ kg gliclazide treatment. Conclusions: This treatment decreased neutrophil and macrophage migration, decreased the inflammatory response, and decreased bone loss in rats with ligature-induced periodontitis

The Enteric Glial Network Acts in the Maintenance of Intestinal Homeostasis and in Intestinal Disorders

The enteric nervous system (ENS), also known as second brain, innervates our gastrointestinal tract controlling its functions, such as motility, fluid secretion, nutrient absorption, and even involvement in the control of immunity and inflammatory processes. In the gut, the gliocytes are known as enteric glial cells (EGCs). Enteric glial cells form a network that permeates the entire gut. Enteric glia express the cell surface hemichannel of connexin-43 (Cx43) necessary for the propagation of Ca2 + responses, necessary to maintain their functions. In this chapter, besides the development of ENS and its glial cells and the similarities with the astrocytes in the central nervous system, we approached the important role of the glial network in the control of gut homeostasis, in the interaction with the immune system, and its participation in pathological conditions. EGCs are even capable of replacing lost neurons. Thus the enteric glia is a multifunctional cell, which through its multiple interactions maintains the integrity of the ENS allowing it to be resistant to the different and constant aggressions suffered by the digestive system

Effects of hecogenin and its possible mechanism of action on experimental models of gastric ulcer in mice

This study investigates the gastroprotective effects of hecogenin, a steroid saponin isolated from Agave sisalana, on experimental models of gastric ulcer. Male Swiss mice were used in the models of ethanol-and indometacin-induced gastric ulcer. To clarify the hecogenin mechanism of action, the roles of nitric oxide (NO), sulfhydryls (GSH), K-ATP(+) channels and prostaglandins were also investigated, and measurements of lipid peroxidation (TBARS assay) and nitrite levels in the stomach of hecogenin-treated and untreated animals were performed. Furthermore, the effects of hecogenin on myeloperoxidase (MPO) release from human neutrophils were assessed in vitro. Our results showed that hecogenin (3.1, 7.5, 15, 30, 60 and 90 mg/kg, p.o.) acutely administered, before ethanol or indomethacin, exhibited a potent gastroprotective effect. Although the pretreatments with L-NAME, an iNOS inhibitor, and capsazepine, a TRPV1 receptor agonist, were not able to reverse the hecogenin effect, this was reversed by glibenclamide, a K-ATP(+) blocker, and indomethacin in the model of ethanol-induced gastric lesions. the hecogenin pretreatment normalized GSH levels and significantly reduced lipid peroxidation and nitrite levels in the stomach, as evaluated by the ethanol-induced gastric lesion model. the drug alone increased COX-2 expression and this effect was further enhanced in the presence of ethanol. It also decreased MPO release and significantly protected the gastric mucosa. in conclusion, we showed that hecogenin presents a significant gastroprotective effect that seems to be mediated by K-ATP(+) channels opening and the COX-2/PG pathway. in addition, its antioxidant and anti-inflammatory properties may play a role in the gastroprotective drug effect. (C) 2012 Elsevier B. V. All rights reserved.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Univ Fed Ceara, Dept Physiol & Pharmacol, BR-60431270 Fortaleza, Ceara, BrazilUniv Fed Ceara, Dept Pharm, BR-60431270 Fortaleza, Ceara, BrazilUniv Fed Paraiba, Dept Pharmaceut Sci, BR-58100000 Joao Pessoa, Paraiba, BrazilUniv Fed Ceara, Dept Morphol, BR-60431270 Fortaleza, Ceara, BrazilUniversidade Federal de São Paulo, Dept Pharmacol, BR-04044020 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Pharmacol, BR-04044020 São Paulo, BrazilWeb of Scienc

Omega-3 fatty acids: possible neuroprotective mechanisms in the model of global ischemia in rats

Background. Omega-3 (omega 3) administration was shown to protect against hypoxic-ischemic injury. The objectives were to study the neuroprotective effects of omega 3, in a model of global ischemia. Methods. Male Wistar rats were subjected to carotid occlusion (30 min), followed by reperfusion. The groups were SO, untreated ischemic and ischemic treated rats with omega 3 (5 and 10 mg/kg, 7 days). The SO and untreated ischemic animals were orally treated with 1% cremophor and, 1 h after the last administration, they were behaviorally tested and euthanized for neurochemical (DA, DOPAC, and NE determinations), histological (Fluoro jade staining), and immunohistochemical (TNF-alpha, COX-2 and iNOS) evaluations. The data were analyzed by ANOVA and Newman-Keuls as the post hoc test. Results. Ischemia increased the locomotor activity and rearing behavior that were partly reversed by omega 3. Ischemia decreased striatal DA and DOPAC contents and increased NE contents, effects reversed by omega 3. This drug protected hippocampal neuron degeneration, as observed by Fluoro-Jade staining, and the increased immunostainings for TNF-alpha, COX-2, and iNOS were partly or totally blocked by omega 3. Conclusion. This study showed a neuroprotective effect of omega 3, in great part due to its anti-inflammatory properties, stimulating translational studies focusing on its use in clinic for stroke managing.Faculty of Medicine, Estácio of Juazeiro do Norte (FMJ), Rua Tenente Raimundo Rocha 515, 63040-360 Juazeiro do Norte, CE, BrazilFederal University of Ceará (UFC), Rua Coronel Nunes de Melo 1127, 60430-270 Fortaleza, CE, BrazilFederal University of São Paulo (UNIFESP), Rua Pedro de Toledo 669, 04039-032 São Paulo, SP, BrazilFederal University of São Paulo (UNIFESP), Rua Pedro de Toledo 669, 04039-032 São Paulo, SP, BrazilWeb of Scienc