Experimental Model of Arthritis Induced by Paracoccidioides brasiliensis in Rats

Paracoccidioidomycosis (PCM), a disease caused by the fungus Paracoccidioides brasiliensis (Pb), is highly prevalent in Brazil, where it is the principal cause of death by systemic mycoses. The disease primarily affects men aged 30-50 year old and usually starts as a pulmonary focus and then may spread to other organs and systems, including the joints. The present study aimed to develop an experimental model of paracoccidioidomycotic arthritis. Two-month-old male Wistar rats (n = 48) were used, divided in 6 groups: test groups EG/15 and EG/45 (received one dose of 100 mu l of saline containing 10(5) Pb viable yeasts in the knee); heat killed Pb-group HK/15 and HK/45 (received a suspension of 10(5) Pb nonviable yeasts in the knee) and control groups CG/15 and CG/45 (received only sterile saline in the knee). The rats were killed 15 and 45 days postinoculation. In contrast with the control rats, the histopathology of the joints of rats of the test groups (EG/15 and EG/45) revealed a picture of well-established PCM arthritis characterized by extensive sclerosing granulomatous inflammation with numerous multiple budding fungal cells. The X-ray examination revealed joint alterations in these groups. Only metabolic active fungi evoked inflammation. The experimental model was able to induce fungal arthritis in the knees of the rats infected with metabolic active P. brasiliensis. The disease tended to be regressive and restrained by the immune system. No evidence of fungal dissemination to the lungs was observed.

Purificação e caracterização da VDAC de mitocôndrias corticais aviares: identificação de modificações pós-traducionais nas porinas neuronais murinas e aviares

A VDAC é uma porina presente na MME cuja função é crucial no metabolismo energético, sobrevivência e morte celular. A caracterização da VDAC torna-se importante para a compreensão das inter-relações da mitocôndria com os diferentes componentes citosólicos, tais como a HK. A ligação HK-VDAC favorece a utilização do ATP intramitocondrial em células neuronais, a HK cerebral pode interagir de formas diferentes com a VDAC, o que resulta em diferentes sítios de ligação (sítios A e B). Os variados papéis metabólicos das isoformas da VDAC podem ser explicados pela presença de alterações pós-traducionais. No presente trabalho purificamos a VDAC1 mitocondrial neuronal proveniente de cérebro aviar. Paralelamente, comprovamos que a presença de múltiplas formas das VDACs 1 e 2 em cérebros murino e aviar, seja devida à presença de modificações pós-traducionais, nomeadamente a fosforilação. A proteína isolada apresentou peso molecular de 30KDa. Quando submetida à eletroforese e posteriormente à coloração para a identificação de fosfoproteínas, a mesma mostrou-se desfosforilada. O conhecimento da presença, ou ausência de fosforilação das VDACs, reside na importância de estabelecer-se as bases moleculares ligadas à existência de sítios A e B nas mitocôndrias neuronais.

Human Leucocytes Response to Viable, Extended Freeze-Drying or Heat-Killed Mycobacterium bovis bacillus Calmette-Guerin

We investigated the effects of viable, extended freeze-drying (EFD) or heat-killed (HK) Mycobacterium bovis bacillus CalmetteGuerin (BCG) in respiratory burst activity, gene expression of CYBB and NCF1 encoding components of the human phagocyte nicotinamide adenine dinucleotide (NADPH) oxidase, TLR2 expression, and in IL-10 and TNF-a cytokine production by human peripheral blood mononuclear cells (PBMCs). Viable BCG significantly inhibited TLR2 and CYBB gene expression, as well as superoxide release by human PBMC. All BCG stimuli augmented IL-10 release, but only HK BCG or viable BCG increased TNF-a release by PBMCs. Our studies show that viable BCG can impair the NADPH oxidase system activation and the TLR2 route in human PBMCs. As well, different BCG preparations can distinctly influence cytokine production by human PBMCs.

Carvedilol protects against apoptotic cell death induced by cisplatin in renal tubular epithelial cells

Cisplatin is a highly effective chemotherapeutic drug; however, its use is limited by nephrotoxicity. Studies showed that the renal injury produced by cisplatin involves oxidative stress and cell death mediated by apoptosis and necrosis in proximal tubular cells. The use of antioxidants to decrease cisplatin-induced renal cell death was suggested as a potential therapeutic measure. In this study the possible protective effects of carvedilol, a beta blocker with antioxidant activity, was examined against cisplatin-induced apoptosis in HK-2 human kidney proximal tubular cells. The mitochondrial events involved in this protection were also investigated. Four groups were used: controls (C), cisplatin alone at 25 mu M (CIS), cisplatin 25 mu M plus carvedilol 50 mu M (CV + CIS), and carvedilol alone 50 mu M (CV). Cell viability, apoptosis, caspase-9, and caspase-3 were determined. Data demonstrated that carvedilol effectively increased cell viability and minimized caspase activation and apoptosis in HK-2 cells, indicating this may be a promising drug to reduce nephrotoxicity induced by cisplatin.