Expression profile of endothelin receptors (ETA and ETB) and microRNAs-155 and -199 in the corpus cavernosum of rats submitted to chronic alcoholism and diabetes mellitus

Recent evidence shows that chronic ethanol consumption increases endothelin (ET)-1 induced sustained contraction of trabecular smooth muscle cells of the corpora cavernosa in corpus cavernosum of rats by a mechanism that involves increased expression of ETA and ETB receptors. Our goal was to evaluate the effects of alcohol and diabetes and their relationship to miRNA-155, miRNA-199 and endothelin receptors in the corpus cavernosum and blood of rats submitted to the experimental model of diabetes mellitus and chronic alcoholism. Forty-eight male Wistar rats were divided into four groups: control (C), alcoholic (A), diabetic (D), and alcoholic-diabetic (AD). Samples of the corpus cavernosum were prepared to study the protein expression of endothelin receptors by immunohistochemistry and expression of miRNAs-155 and -199 in serum and the cavernous tissue. Immunostaining for endothelin receptors was markedly higher in the A, D, and AD groups than in the C group. Moreover, a significant hypoexpression of the miRNA-199 in the corpus cavernosum tissue from the AD group was observed, compared to the C group. When analyzing the microRNA profile in blood, a significant hypoexpression of miRNA-155 in the AD group was observed compared to the C group. The miRNA-199 analysis demonstrated significant hypoexpression in D and AD groups compared to the C group. Our findings in corpus cavernosum showed downregulated miRNA-155 and miRNA-199 levels associated with upregulated protein expression and unaltered mRNA expression of ET receptors suggesting decreased ET receptor turnover, which can contribute to erectile dysfunction in diabetic rats exposed to high alcohol levels.

Clororpromazina e função mitocondrial na isquemia-reperfusão renal

The purpose of this study was to evaluate the function of mitochondria obtained from kidneys submmited to 48 hours of cold ischemia followed by 1 hour of reperfusion, with and without the use of chlorpromazine. Sixteen adult mongrel dogs were submitted to unilateral nephrectomy. In 13 animals the kidney was then perfused with Euro-Collins solution and preserved during 48-hours in cold solution. After that time auto-transplantation was performed. Reperfusion time was 1 hour. After that, the transplanted kidney was taken out and samples were obtained for mitochondrial evaluation. The animals were divided into 3 groups: group N - control without ischemia (3 animals); group I - hypothermia (6 animals); group II - hypothermia + IV injection of 2 mg/Kg of chlorpromazine 15 minutes before nephrectomy. The results of mitochondrial phosphorilation and swelling showed no statistical differences. However, group II animals showed higher values during the reversion phase of the swelling. Chlorpromazine action on mitochondrial function has been previously described, providing better mitochondria recovering from ischemic lesion. The results obtained in this study may be related to the short reperfusion time, or we can argue that chlorpromazine has no protection after prolonged ischemic time, or chlorpromazine action may be masqueraded by hypothermia.

Introdução e objetivo - em transplante renal com doador cadáver, a função do enxerto depende da manutenção da integridade celular e subcelular, principalmente mitocondrial. Neste estudo o objetivo foi analisar a função mitocondrial do rins submetidos a período prolongado de isquemia fria, seguido de reperfusão por uma hora, empregando-se, ou não, a clorpromazina previamente à isquemia. Métodos - utilizando autotransplante renal em cães, subdivididos em dois grupos, foram extraidas mitocôndrias de rins submetidos à isquemia fria de 48 horas, seguida de 1 hora de reperfusão pós-transplante. Um grupo recebeu clorpromazina antes da nefrectomia. A análise da fosforilação oxidativa e do intumescimento osmótico ("swelling") mitocôndrial foi comparada com dados obtidos de rins normais, sem isquemia. Resultados - Os dados obtidos para o estado III e IV da respiração não mostraram diferença significativa entre os grupos experimentais. A primeira fase do "swelling" ocorreu em tempo semelhante em todos os grupos experimentais. Durante a reversão, os grupos I e II se comportaram de maneira estatisticamente semelhante, com frações de reversão de 57%, e 68%, respectivamente, valores significativamente menores que os obtidos para o grupo normal (99%) (grupo I: p = 0,0374 e grupo II: p = 0,0221). Discussão - é conhecida a ação protetora da clorpromazina na isquemia renal normotérmica. Entretanto, os dados aqui obtidos mostram que após 48 horas de isquemia fria, o grupo II (clorpromazina) comportou-se de maneira semelhante ao grupo I (hipotermia isolada) tanto no estudo da fosforilação oxidativa, quanto no "swelling", embora os valores apresentem tendência a serem maiores no grupo II. Isto pode ser devido a alguns fatores, como: 1) a clorpromazina possui efeito protetor mínimo quando o tempo de isquemia é prolongado; 2) seu efeito pode ser afetado ou sua ação protetora sobreposta àquela imposta pela hipotermia; 3) tempo de reperfusão curto para manifestação de seus efeitos.