Comparative analysis of different doses of coherent light (laser) and non-coherent light (light-emitting diode) on cellular necrosis and apoptosis: a study in vitro

Introduction Threshold doses of electromagnetic radiation can initiate necrosis and apoptosis in cells. The purpose of this study was to evaluate cellular apoptosis and necrosis immediately (t0) and 24 hours (t24) after irradiation with different doses of coherent light (laser) or non-coherent light (LED). Methods CHO-K1 lineage cells were irradiated with laser (810nm) or LED (945±20nm), with 24mW, contact area of 1cm2 and doses of 10, 20, 30, 40 and 50J/cm2 for 300, 660, 960, 1230 and 1620s, respectively, at both wavelengths. Cells were evaluated by fluorescence microscopy, differentiating viable, apoptotic and necrotic cells immediately and 24 hours after irradiation. Results The number of necrotic cells at t0 was higher in the LED 40 and 50J/cm2 groups (86±14 and 84±16% respectively, p <0.05), than in the 10 and 20J/cm2 laser (5±2 and 5±3%, p<0.05) and LED (5±3 and 4±1%, p<0.05) conditions. At t24, the LED 40J/cm2 (80±20%, p<0.05) group also showed more necrosis than the control and lower dose groups (laser 10, 20, and 30J/cm2 percentage of 6±4, 10±3 and 7±3%, p<0.05; LED 10 and 20J/cm2 percentage of 3±1 and 17±10%, p<0.05). A decrease in apoptotic cells was observed in the laser group with doses of 10, 40, and 50J/cm2 (6±4, 3±1 and 1±1% respectively, not significant), as well as in the LED 40J/cm2 (2±2%, not significant) group versus control. The cells had a higher percentage of apoptosis cells in the control group and with laser doses of 10 and 30J/cm2 (percentage of 20±1 and 20±4%, not significant), while only the LED 40J/cm2 (10±10%, not significant) had a lower percentage compared the control group. Conclusion Laser or LED stimulation promoted an increase in cell necrosis in a high energy density condition as characterized in a dose-dependent inhibition therapy. Laser or LED infrared irradiation in low doses (up to 20J/cm2) reduced the percentage of apoptosis in CHO-K1 cells, while high doses (30J/cm2) elevated apoptosis.

Uso de fibrinógeno humano en la generación de soportes para la obtención de equivalentes tisulares / Use of human fibrinogen in the generation of scaffold for obtaining Tissue equivalents

Desde sus orígenes, la Ingeniería de Tejidos ha buscado diversos materiales que puedan ser utilizados para la generación de soportes que sirvan para el anclaje, proliferación y diferenciación celular que conduzcan a la obtención de tejidos humanos. Muchos materiales de tipo cerámico, polimérico y metálico se han evaluado, pero hasta la fecha muchos de ellos han sido rechazados por diversas razones, entre otras su escasa biocompatibilidad y biodegradabilidad, la respuesta inmune generada, la baja resistencia mecánica o el riesgo de transmisión de virus o priones. El fibrinógeno es una proteína presente en el plasma sanguíneo que puede ser utilizada para la generación de soportes tridimensionales que favorezcan el crecimiento de células; se obtiene a partir del propio paciente, bancos de sangre o como proteína purificada (Tisseel® o Tissucol®, Laboratorios Baxter). El fibrinógeno evita el desencadenamiento de una respuesta inmunológica y el uso de productos xenogénicos. Debido a la estructura proteica, la adhesión y proliferación celular se ven favorecidas dando excelentes resultados en la generación de equivalentes de piel, cartílago, córnea y reemplazos cardiacos en aplicaciones in vitro e in vivo. Como desventajas presenta su rápida degradación y su baja resistencia mecánica; sin embargo, en los últimos años se han venido evaluando mezclas con algunos biopolímeros como ácido poliláctico (PLLA), ácido poli-glicólico (PGA) y alginato de sodio. Esta revisión presenta algunas de las principales aplicaciones del fibrinógeno en Ingeniería de Tejidos.

Since its origin, Tissue Engineering has sought various materials that can be used for generation of scaffolds that serve to anchor, proliferation and cell differentiation leading to the production of human tissues. Many materials such as ceramic, polymeric and metal type have been evaluated to date but many have been rejected for various reasons, including its limited biocompatibility and biodegradability, immune response generated, low mechanical strength or the risk of transmission of virus or prions. Fibrinogen is a protein present in blood plasma that can be used to generate three-dimensional scaffolds that favors growth of cells, it is obtained from the patient itself, bank of blood or purified protein (Tisseel® or Tissucol®, Laboratorios Baxter). Fibrinogen acts slowing or reversing the immune response and avoiding the use of xenogeneic materials. Because the protein structure, adhesion and cell proliferation is favored with excellent results in the generation of skin equivalents, cartilage, cornea and even heart replacements in vitro and in vivo. The disadvantages presented are the rapid degradation and low mechanical strength, but in recent years it has been evaluating some biopolymer mixtures as polylactic acid (PLLA), poly-glycolic acid (PGA) and sodium alginate. This review presents some of the main applications of fibrinogen in Tissue Engineering.

MALIGNANT TRANSFORMATION OF MIXED CULTURE CELLS OF LUNG AND LIVER OF NEW BORN MOUSE INDUCED BY~3H-TdR AND ITS CHROMOSOME ANALYSIS / 解剖学报

In this experiment, primary mixed culture cells of lung and liver derived from new born mouse was made use of target cells, 0.1 ?Ci 3~H-TdR per milliliter medium was added in the culture in order to induce malignant transformation of the cells in the culture. Results of the experiment was that the cells effected by 3~H-TdR had a unlimited growing and formed sarcoma after being inoculated into new born mice immunosuppressed with ATS. It suggested that they had became malignant transformation cells. Results of analysis of chromosome aberrations of the transformed cells, the long arm chromosome was observed in 5% of cells, the metacentric chromosome in 7% of cells, the acentric fregment in 8% of cells. It shows that DNA damage of the cells induced by 3~H-TdR causes their chromosome aberrations and, futhermore, development of malignant cells. The fact that unstable aberrations was Still in sight in the malignant transformation cells suggested that there have been a bit of 3~HTdR left in these cells which kept damaging DNA of the cells.