Efecto cardíaco del extracto de epitelio pigmentado de la retina (melanina), del globo ocular de embrión de pollo “in vivo” e “in vitro” / Cardiac effect of the extract of retinal pigment epithelium (melanin) of the eyeball chick embryo

La melanina y su participación en la génesis de ciertas patologías cardíacas, ha sido revisada recientemente. Sin embargo, la expresión funcional y celular del efecto sobre el corazón no ha sido claramente establecida. En el presente trabajo se hizo uso del extracto de epitelio pigmentado de la retina del globo ocular de embrión de pollo, contentivo de melanina, para estudiar "in vivo" el patrón de contracción del corazón y la frecuencia cardíaca por videocardiograma, un método semi-invasivo en embriones de pollo de 3d-4d días de incubación, e "in vitro", su efecto sobre el patrón mitocondrial de mioblastos cardíacos en cultivo primario de Gota pendiente, incubados con el fluorocromo catiónico, 3,3´-dimetiloxicabonocianida (DiOC1 [3]). El tratamiento promovió una disfunción de la contracción peristáltica del corazón embrionario, con un incremento en el llenado auricular y una reducción de llenado ventricular durante las diástoles. Se determinó una reducción significativa de frecuencia cardíaca del 18,73 por ciento, luego de una hora de tratamiento. A diferencia de los controles, con un patrón homogéneo de fluorescencia verde emitido por las mitocondrias de forma alargada, la población de mioblastos tratados mostró un patrón de fluorescencia difusa, mitocondrias redondeadas y se observó la presencia de blebs a nivel de la superficie celular. Los resultados sugieren que el extracto de epitelio pigmentado de retina, contentivo de melanina, altera la contracción peristáltica e induce una reducción de la frecuencia cardíaca en modelo experimental de embrión de pollo, acompañada con un daño en las mitocondrias, probablemente vinculado a la activación de un proceso de muerte celular mediado por factores apoptoticos mitocondriales que podrían estar asociados a tales efectos

Melanin and its involvement in the genesis of certain cardiac diseases, has recently been revised. However, the expression of functional and cellular effects on the heart has not been clearly established. In this paper we made use of the extract of the retinal pigmented epithelium of the eyeball of the chick embryo, containing melanin, to study "in vivo" the pattern of contraction of the heart and the heart rate by Videocardiograma semi-invasive method in embryos of 3d-4d days of incubation, and in vitro, their effect on the pattern of mitochondrial using Hanging drop method, to primary culture of cardiac myoblasts, incubated with the cationic fluorochrome, 3,3-dimetiloxicabonocianida (DiOC1 [3]). The treatment promoted a malfunction of the peristaltic contraction of the embryonic heart, with an increase in atrial filling and reduced ventricular filling during diastole. We determined a significant reduction in heart rate of 18.73 percent, after an hour of treatment. The population of myoblasts showed a diffuse pattern of fluorescence, mitochondria were rounded and the cytoplasm showed the presence of blebs at the surface unlike controls with a uniform pattern of green fluorescence emitted by the elongated shape of mitochondria. The results suggested that the extract of retinal pigmented epithelium, melanin containing, alters the peristaltic contraction and decrease the heart rate in experimental model of chick embryo, together with mitochondrial damage, probably linked to the activation of a process of cell death mediated by factors apoptotic mitochondria, which could be associated with such effects

The Role of Calcium Affecting Signal Pathway Related to Nitric Oxide-induced Cytotoxicity in H9c2 Cardiac Myoblast / 대한해부학회지

Nitric oxide (NO) elevates intracellular calcium. But the actions of calcium in NO-induced cell death are not well understood. This study was carried out to investigate the signal transduction pathways of calcium and NO-induced cytotoxicity in H9c2 cardiac myoblasts by using NO donor compounds such as sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine (SNAP). Pretreatment of intracellular calcium chelating agent (BAPTA/AM) or L-type calcium channel blockers (nicardipine, nifedipine, diltiazem and veraparmil) or T-type calcium channel blocker (flunarizine) blocked SNP-induced cytotoxicity respectively only in a three hours. However, thapsigargin (TG), which inhibits endoplasmic reticulum dependent Ca(2+)-ATPase and thereby increases cytosolic Ca(2+), augmented SNP-induced cytotoxicity. The protective effect of BAPTA/AM was inhibited by treatment of protein synthesis inhibitor, cyclohexamide. In addition, pyrrolidine dithiocarbamate (PDTC), NF-kB inhibitor, attenuates the protective effect of BAPTA/AM against SNP-induced cytotoxicity. It is indicated that the protective effect of BAPTA/AM against NO-induced cytotoxicity might be due to the expression of protein related to activation of NFkB. From these results, it is concluded that SNP-induced cytotoxicity is mediated by calcium in a 3 hours via down regulation of protein expression rleated to activation of NFkB.