Estudo do efeito anti-apoptótico do Mycobacterium leprae em células de Schwann humanas / Study of the anti-apoptotic effect of the Mycobacterium leprae in human Schwann cells

A Hanseníase, causada pelo Mycobacterium leprae, apresenta como sintoma clínico mais relevante lesões no sistema nervoso periférico. As estratégias utilizadas pelo M. leprae para infectar e se multiplicar nas células de Schwann (CS) são,contudo,pouco conhecidas. Neste trabalho investigamos o efeito anti-apoptótico do M. leprae sobre a célula hospedeira,à semelhança do observado na literatura com outros patógenos intracelulares obrigatórios. Para tal, CS humanas da linhagem ST88-14 foram tratadas ou não com a bactéria e incubadas em meio RPMI sem soro para induzir a apoptose. A viabilidade celular foi avaliada por 3 métodos: i) redução enzimática de Metiltetrazólio (MTT), ii)capacidade celular de excluisão do corante Azul de Tripan e iii) coloração vital com diacetato de fluoresceína e brometo de etídio. Após 24-48h de incubação, as células tratadas com M.leprae apresentaram índices de sobrevivência de 70-100por cento, contrastando com as culturas não tratadas com a bactéria que apresentaram índice de sobrevivência entre 30-60por cento. M. leprae foi capaz de proteger as CS da morte de maneira dose-dependente. A redução de células entrando em apoptose pela presença do bacilo também foi observada através da avaliação do potencial de membrana mitocondrial com o corante DiOC6 por Citometria de Fluxo. Em seguida demonstramos que fatores solúveis secretados pela célula incubada com M.leprae estão envolvidos na proteção, visto que o meio condicionado proveniente de culturas tratadas também promoveu a sobrevivência de CS. Possíveis candidatos para estes fatores de sobrevivência seriam os Fatores de Crescimento semelhantes à Insulina, IGF-I e IGF-II. Confirmamos, então, a capacidade de M. leprae induzir a expressão de IGF-I e IGF-II em CS através da técnica de RT-PCR. Também demonstramos que IGF-I recombinante adicionado às culturas foi capaz de proteger as CS ST 88-14 de morte induzida por privação de soro. A ação do IGF-I é possivelmente mediada pelo seu receptor...

Probiotic amelioration of azotemia in 5/6th nephrectomized Sprague-Dawley rats.

The present study was to test the hypothesis that, selected bacteria instilled into the gastrointestinal tract could help in converting nitrogenous wastes accumulated due to renal insufficiency into non-toxic compounds; thereby, ameliorating the biochemical imbalance. Herein we describe a prospective, blinded, placebo controlled pilot-study, using 5/6th nephrectomized Sprague Dawley rat, as a chronic renal failure model. The study group consisted of 36 nephrectomized and 7 non-nephrectomized (control) rats. After two-week nephrectomy stabilization, cohorts of six nephrectomized rats were fed casein-based diet plus one of the following regimens: (A) Control, (B) Placebo (casein-based diet without probiotics), (C) Bacillus pasteurii, (D) Sporolac(R), (E) Kibow cocktail, (F) CHR Hansen Cocktail, and (G) ECONORM. Subsequently, blood (retro-orbital) and urine (collected for measurements of blood urea-nitrogen and creatinine respectively), body weight and bacterial counts (feces) were obtained at regular intervals. The study end-points were to determine if any of the probiotic dietary supplements facilitated, (1) decreased blood concentrations of uremic toxins, (2) altered renal function, and (3) prolonged survival. After 16 weeks of treatment, regimens C and D significantly prolonged the life span of uremic rats, in addition to showing a reduction in blood urea-nitrogen levels, concluding that supplementation of probiotic formulation to uremic rats slows the progression of azotemia, which may correlate with prolonged life span of uremic rats. Derivative trials of probiotic treatment of larger animals and humans will further assess the potential role of probiotic formulations in delaying the onset and clinical severity of clinical illness at different stages of renal failure.

The effects of different beak trimming techniques on plasma corticosterone and performance criteria in Single Comb White Leghorn hens.

DeKalb XL chicks were given a beak trim at 6 d of age (6DP) with a 2.8-mm gauge and a beak trim at 11 wk (11WB) with a block cut approximately 2 mm anterior to the nasal openings. Corticosterone (CS) levels of the 6DP treatment were (P < or = 0.01) elevated above nontrimmed CS levels at 2 h posttrim; and BW and feed consumption (FC) of the 6DP were depressed until 8 wk of age. At 11 wk of age, CS of the 11WB treatment was (P < or = 0.02) elevated above controls at 1, 2, 8, and 5 wk posttrim. The 11WB treatment resulted in a decrease in FC and a reduction in BW at 12, 14, and 16 wk of age, whereas there were no differences among treatments in livability during the pullet phase. At 72 wk of age, FC of the nontrimmed controls was greater than both beak trimmed treatments, and both beak trimmed treatments had greater hen housed eggs, percentage hen day egg production, and percentage livability. Both beak trimmed treatments resulted in better egg income, feed cost per hen, and net income (NI). The 6DP and 11WB beak trim treatments resulted in an improvement of NI per hen of 1.48 dollars and 1.86 dollars, respectively. In addition, both beak trimmed treatments exhibited better feather score and Hansen's test (fearfulness). It was concluded that pullets and hens could adapt to the physiological stress of beak trimming and out perform, during a lay phase, controls whose beaks were not trimmed.