Efecto del láser infrarrojo sobre células tiroideas / Infrared laser effect on thyroid cells

Diez ratas Sprague Dawley de 4 meses de vida y peso aproximado de 250 g fueron divididas en dos grupos de 5 animales cada uno, el grupo A se mantuvo como control y los animales del grupo B recibieron estimulaciones con láser infrarrojo en la tiroides con dosis de 16 J/cm2 durante 15 días consecutivos. Posteriormente las ratas fueron sacrificadas, se extrajeron las respectivas tiroides siendo procesadas para microscopía óptica y se obtuvieron placas histológicas y micrografías de tiroides con aumentos finales de hasta 1000X, las cuales fueron sometidas a estudios morfométricos para determinar en 100 células foliculares: número, áreas y perímetro tanto celular como nuclear, además de disposición coloidal y presencia de vasos sanguíneos. El análisis de los resultados entre las 100 células foliculares pertenecientes a tiroides normal y estimulada revela que existen marcadas diferencias en todos los componentes analizados los que se podría traducir en distintas funcionalidades en el metabolismo de las respectivas glándulas.

Ten 4-month-old Sprague Dawley rats weighing approximately 250 g were divided into two groups of 5 animals each. Group A was the control and the animals in group B received thyroid stimulation with infrared laser in a dose of 16 J/cm2 for 15 consecutive days. Subsequently, rats were euthanized and thyroids were removed and processed for optical microscopy. From both cell types thyroid histological slides and micrographs were obtained with final increases of 400 and 1000X. Morphometric analysis determined the number, areas and cell perimeter as well as colloidal dispersion and presence of blood vessels in 100 follicular cells. Analysis of the results among the 100 follicular cells belonging to normal and stimulated thyroids revealed marked differences in all the analyzed components, which could translate into different functionalities in the metabolism of the respective glands.

Effect of ceramide on apoptosis and phospholipase D activity in FRTL-5 thyroid cells

Ceramide, a product of sphingomyelin hydrolysis, is now recognized as an intracellular lipid messenger, which mediates the effects of extracellular agents on cellular growth, differentiation and apoptosis. Recently, ceramide has been implicated in the regulation of phospholipase D (PLD). In this study, we examined the effects of ceramide on the activity and mRNA level of PLD during apoptotic process in FRTL-5 thyroid cells. C2-ceramide (N-acetyl sphingosine) induced apoptosis in FRTL-5 thyroid cells. Fluorescent staining showed that ceramide induced the typical features of apoptosis including condensed or fragmented nuclei. DNA fragmentation was also observed by agarose gel electrophoresis. Flow cytometric cell cycle analysis showed more clearly that ceramide induced apoptotic cell death in FRTL-5 thyroid cells. The treatment of FRTL-5 thyroid cells with thyroid-stimulating hormone (TSH) resulted in an increased PLD activity in a dose- and time-dependent manner. However, the TSH-induced increase in PLD activity was down-regulated within 2 h after ceramide treatment. Furthermore, the levels of PLD mRNA were found to be decreased throughout apoptotic process as inferred by reverse transcription-polymerase chain reaction. However, the decreases in PLD mRNA levels were not correlated with those in PLD activities after ceramide treatment. Taken together, these data suggest that ceramide inhibits the PLD activity in an early apoptotic phase and down-regulation of the levels of PLD mRNA may be implicated in apoptotic process in FRTL-5 thyroid cells.