Efeitos da arginina na reparação cicatricial na parede abdominal de ratos wistar

Orientador: Prof. Dr. Jorge R. Ribas TimiCoorientador: Prof. Dr. Jorge Eduardo Fouto MatiasDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências da Saúde, Programa de Pós-Graduação em Clínica Cirúrgica. Defesa: Curitiba, 08/07/2016Inclui referências: f. 66-71Área de concentração : Nutrição e cicratizaçãoResumo: INTRODUÇÃO: a cicatrização de feridas é um processo dinâmico que envolve vários fenômenos biológicos e bioquímicos os quais podem ser minimizados em condições patológicas ou melhorados pela oferta de fatores de crescimento ou de condições de crescimento teciduais. O óxido nítrico como o produto da reação de óxido-redução da arginina (ARG) estimula a proliferação dos angioblastos, células precursoras do endotélio. Consequentemente ocorre formação de novos vasos sanguíneos no tecido e possivelmente coopera para a melhora do processo cicatricial. OBJETIVO: avaliar os efeitos da arginina na cicatrização da parede abdominal em ratos Wistar. MÉTODO: utilizaram-se vinte ratos Wistar, submetidos à laparotomia-laparorrafia e separados em dois grupos. No grupo arginina receberam tratamento diário, por cinco dias, com ARG (300mg/kg/dia) via intraperitoneal. No grupo controle foram tratados diariamente com solução tampão fosfatos em dose equivalentes ao peso, pela mesma via do grupo arginina. No sétimo dia pósoperatório coletaram-se amostras de sangue e a cicatriz da parede abdominal de ambos os grupos. Avaliaram-se o nível sérico de nitratos e nitritos, a evolução cicatricial pelas dosagens de hidroxiprolina tecidual, formação de tecido de granulação, determinação da porcentagem de colágeno maduro e imaturo, densidade de miofibroblastos e angiogênese. Empregaram-se os testes de ANOVA e T-Student com p 0,05 para as comparações entre os grupos. RESULTADOS: entre os grupos controle e tratado por arginina, não ocorreram diferenças significantes nas dosagens de nitratos e nitritos (p=0,9903), hidroxiprolina tecidual (p=0,1315) e na densidade de miofibroblastos (p=0,0511). O grupo arginina apresentou maior densidade microvascular (p=0,0008), maior porcentagem de colágeno tipo I (p=0,0064) e melhora na formação do tecido de granulação com melhores índices de proliferação angiofibroblástica (p=0,0007) e reepitelização das bordas (0,0074). CONCLUSÃO: na avaliação cicatricial da parede abdominal de ratos Wistar sob tratamento com arginina por sete dias não houve alteração do nível sérico de nitratos e nitritos, da deposição de colágeno total e da densidade de miofibroblastos. Verificaram-se aumento da maturação de colágeno do tipo I, da densidade microvascular e melhora na formação do tecido de granulação cicatricial pelas melhores reepitelização de bordas e proliferação angiofibroblástica. Descritores: arginina, cicatrização, hidroxiprolina, angiogênese, CD34, miofibroblastos, colágeno tipo I, picro-sirius, anti actina alfa, nitratos e nitritos, ratos Wistar, parede abdominal.Abstract: INTRODUCTION: wound healing is a dynamic process involving several biological and biochemical phenomena which can be minimized in pathological conditions or improved if a correct supply of growth factors or proper tissue growing conditions are in course. Nitric oxide as the product of the arginine (ARG) reduction reaction stimulates the proliferation of angioblasts, endothelial cell precursors. Consequently there is formation of new blood vessels in the reparation tissue that, probably, improves the healing process. OBJECTIVE: to evaluate the effects of arginine on the abdominal wall healing process in rats. METHOD: the study was approved by the Ethics Committee for Animal Research according to the 012/11 HAC protocol. Twenty Wistar rats underwent laparotomy-laparorrhaphy and were separated into two groups. In the arginine group 10 rats received daily treatment for five days, with ARG (300mg / kg / day) intraperitoneally. In the control group the other 10 rats were treated daily with phosphate buffer solution at a dose equivalent to the weight, by the same administration way of the arginine group. On the seventh postoperative day blood samples and the surgical wound of the abdominal wall were collected in both groups. Serum levels of nitrates and nitrites, the scar evolution by measurements of tissue hydroxyproline, granulation tissue formation, the percentage of mature and immature collagen, myofibroblast density and angiogenesis were evaluated. ANOVA and T-Student tests with p 0.05 were employed for comparisons between groups. RESULTS: there were no significant differences in dosages of nitrates and nitrites (p=0,9903), tissue hydroxyproline (p=0,1315) and myofibroblast density (p=0,0511) between the groups. The arginine group had a higher microvascular density (p=0,0008), higher percentage of type I collagen (p=0,0064) and improve in the granulation tissue formation with better angiofibroblastic proliferation index (p=0,0007) and better edges re-epithelialization of the wound (0,0074). CONCLUSION: wound healing evaluation in the abdominal wall of Wistar rats under treatment with arginine, there were no changes in serum levels of nitrates and nitrites, the total collagen deposition and myofibroblasts density. There were increase of type I collagen maturation, microvascular density and improved granulation tissue formation by better edges reepitelization and angiofibroblastic proliferation. Keywords: arginine, wound healing, hydroxyproline, angiogenesis, CD34, myofibroblasts, collagen type I, Sirius red, anti actin alpha, nitrates and nitrites, Wistar rats, abdominal wall

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Catálogo Taxonômico da Fauna do Brasil: setting the baseline knowledge on the animal diversity in Brazil

The limited temporal completeness and taxonomic accuracy of species lists, made available in a traditional manner in scientific publications, has always represented a problem. These lists are invariably limited to a few taxonomic groups and do not represent up-to-date knowledge of all species and classifications. In this context, the Brazilian megadiverse fauna is no exception, and the Catálogo Taxonômico da Fauna do Brasil (CTFB) (http://fauna.jbrj.gov.br/), made public in 2015, represents a database on biodiversity anchored on a list of valid and expertly recognized scientific names of animals in Brazil. The CTFB is updated in near real time by a team of more than 800 specialists. By January 1, 2024, the CTFB compiled 133,691 nominal species, with 125,138 that were considered valid. Most of the valid species were arthropods (82.3%, with more than 102,000 species) and chordates (7.69%, with over 11,000 species). These taxa were followed by a cluster composed of Mollusca (3,567 species), Platyhelminthes (2,292 species), Annelida (1,833 species), and Nematoda (1,447 species). All remaining groups had less than 1,000 species reported in Brazil, with Cnidaria (831 species), Porifera (628 species), Rotifera (606 species), and Bryozoa (520 species) representing those with more than 500 species. Analysis of the CTFB database can facilitate and direct efforts towards the discovery of new species in Brazil, but it is also fundamental in providing the best available list of valid nominal species to users, including those in science, health, conservation efforts, and any initiative involving animals. The importance of the CTFB is evidenced by the elevated number of citations in the scientific literature in diverse areas of biology, law, anthropology, education, forensic science, and veterinary science, among others