Análise histomorfométrica dos cardiomiócitos e deposição de colágeno no músculo cardíaco de ratas ooforectomizadas / Histomorphometric analysis of cardiomyocytes and collagen deposition in the heart muscle of ovariectomized rats

Esse estudo objetivou avaliar o efeito da ooforectomia sob os parâmetros histomorfométricos dos cardiomiócitos e quantificação de colágeno em ratas Wistar. Vinte ratas foram utilizadas e separadas em dois grupos: GI - ooforectomizada e GII - sham-ooforectomizada. Após a recuperação anestésica os animais foram acomodados em gaiolas e separados nas condições de ciclo claro/escuro 12/12h por um período de 6 meses. Passado o período experimental, os animais foram anestesiados, o coração retirado e mergulhado em formaldeído a 10%. Os fragmentos dos ventrículos foram submetidos ao processamento histológico e corados com hematoxilina e eosina. As análises histomorfométricas (área celular e área e volume nuclear) foram realizadas pelo microscópio de luz e software ImageJ versão 1.44. Os dados foram submetidos à análise ANOVA e quando significantes, complementados pelo teste t de student (p<0,001). Observou-se uma diminuição significativa das áreas celular e nuclear dos cardiomiócitos do grupo GI quando comparado ao grupo GII, bem como a área ocupada, pelo colágeno, no músculo cardíaco foi maior em GI, quando comparado a GII. Diante disso, conclui-se que as alterações observadas nos cardiomiócitos do grupo GI, sugerem uma maior atividade apoptótica nesse grupo, devido à diminuição dos níveis séricos do estrógeno provocado pela ooforectomia e o aumento da área ocupada pelo colágeno, no grupo ooforectomizado, está associada ao efeito cardioprotetor do estrógeno.

This study aimed to evaluate the effect of oophorectomy on the morphometric variables of cardiomyocytes and quantification collagen in Wistar rats. Twenty rats were used and divided into two groups: GI - ovariectomized and GII - sham-ovariectomized. After recovery from anesthesia the animals were housed in separate cages and under the conditions of light / dark cycle 12/12h for a period of six months. After the experimental period, the animals were anesthetized, the heart removed and immersed in 10% formaldehyde. The fragments of the ventricles were subjected to histological analysis and stained with hematoxylin and eosin. Histomorphometric analysis (cell area and nuclear area and volume) were performed by light microscopy and ImageJ software version 1.44. The data were submitted to ANOVA and when significant, complemented by Student's t test (p<0.001). There was a significant decrease in cellular and nuclear areas of the GI cardiomyocytes compared to GII and the area occupied by collagen was greater in cardiac muscle GI, when compared to GII. Therefore, it is concluded that the changes observed in the GI group cardiomyocytes, suggest a higher apoptotic activity in this group, due to decreased serum estrogen levels caused by ovariectomy and increased area occupied by collagen in oophorectomized group is associated the cardioprotective effect of estrogen.

En torno a los primeros estudios de electrofisiología / On the first studies of electrophysiology

Se presenta un breve bosquejo histórico de la evolución de la electrología a partir del siglo XVIII. Se discute el tema de la llamada electricidad animal, desde las observaciones sobre las descargas del pez Torpedo hasta las investigaciones del catedrático boloñés Luigi Galvani y de sus discípulos. Sus opositores, encabezados por el físico Alessandro Volta, catedrático en la Universidad de Pavía, opinaban que la electricidad detectada por los galvanistas no era inherente al propio animal, sino debida a la acción de los conductores metálicos empleados para formar el circuito: electricidad de contacto. Sólo a mediados del siglo XIX, el físico Carlo Matteucci logró demostrar la existencia de una verdadera electricidad animal en la forma de corriente de lesión. Se logró cuantificarla gracias a la obtención de un electrómetro satisfactorio construido en 1872 por el físico francés Gabriel Lippmann. Este instrumento fue empleado por el fisiólogo inglés Waller para registrar en humanos los ancestros de los trazos electrocardiográficos (1887). A principios del siglo XX, el holandés Willem Einthoven presentó su galvanómetro de cuerda, que abrió el paso a la electrocardiografía actual. Se logró así registrar los potenciales eléctricos de células miocárdicas primero in vitro, más tarde en corazón canino aislado y perfundido, poco después en corazón in situ y, en fin, en corazón humano. Esto permitió efectuar los actuales mapeos endocárdicos y epicárdicos, indispensables para el diagnóstico y el tratamiento de las arritmias cardiacas.

A historical outline of the evolution of electrophysiology from the eighteenth century is shortly presented. Topics concerning the so called animal electricity starting from the observations on descharges of Torpedo fish until Bolognese Galvani's researches on the frogs are exposed. The points of view of their oppositionists also are examined. These ones, leaded by the physicist Alessandro Volta, professor in the University of Pavia, believed that electricity detected by galvanists was not inherent to animal but was due to the action of the metallic conductors present in the circuit: contact electricity. Only towards the middle of the nineteenth century the physicist Carlo Matteucci attained to demonstrate the existence of the real animal electricity in form of injury current. It was possible to determine that quantitatively thanks to the capillary electrometer built in 1872 by the French physicist Gabriel Lippmann. This instrument was used by the English physiologist Waller in order to obtain the primitive electrocardiographic tracings in humans (1887). At beginnings of the twentieth century, the Dutch professor Willem Einthoven, of the University of Leiden, introduced his string galvanometer which permitted to allow the modern electrocardiography. So it was possible to record the electrical potentials of myocardial cells, first in vitro, later in isolated and perfused heart, son after in dog's heart in situ and finally in human heart. Therefore now it is possible to effectuate endocardial and epicardial mappings, indispensable in order to diagnose and treat the cardiac arrhythmias.

Changes in creatine kinase isoenzyme compositions of skeletal and heart muscles during exercise training in rats / 体力科学

The effect of swimming training on creatine ki nase (CK) isoenzyme compositions (cytoplasmic CK : CK-MM, -MB, -BB ; mitochondrial CK : m-CK) of coleus (SOL), extensor digitorum longus (EDL) and heart muscles were studied. Wistar strain male rats were trained by swimming at a water temperature of 38±2°C, loaded with a weight equal to 5% of their body weight attached to their tails, and made to swim 4-days per week from the age of 4 weeks old for 4, 6 and 8 weeks. CK isoenzyme compositions of SOL, EDL and heart were different from those of other muscles. The activities of CK-MB and m-CK of SOL, EDL and heart increased following exercise training. CK isoenzyme composition of skeletal muscle (SOL and EDL) tended to qualitatively resemble the heart with training. These results suggest that the training-induced metabolic change in skeletal muscle causes similar CK isoenzyme composition to the heart muscle, and ensure energy production for the continuous muscle contraction during endurance exercise. The possibility that the source of the increased serum CK-MB activity after exercise is from the skeletal muscle should be examined thoroughly when the high serum CK-MB activity is interpreted.

Effect of Silybin on Coxsackie B_5 Virus Infected New Born Rat Heart Cells in Culture / 第二军医大学学报

The protective effect of silybin on the micro-model of Coxsackie B5 virus infected new born rat heart cell culture was observed. After inoculation with 400TCID Coxsackie B5 virus, the cardiac enzyme s-lactic acid dehydrogenase (LDH) and glutamic oxaloacctic transaminase (GOT) were much lower in the silybin-treated groups than in those groups of untreated, but the synthesis rate of DNA was higher. Virus titer in the supernatant of cultures was detected 96 h after virus challenge. The virus titer (Lg 3. 95 TCID50) of the silybin-treated was lower than in that of untreated groups (Lg 6. 95 TCID50). These results suggest that silybin may be a useful drug in treatment of acute viral myocarditis.