Résumé
La medicina regenerativa es una rama de la medicina que se ha desarrollado considerablemente en los últimos años. Los avances en este campo se han vinculado estrechamente con los nuevos conocimientos adquiridos sobre las células madre y su capacidad de convertirse en células de diferentes tejidos. Esta medicina se sustenta en conductas adoptadas por el organismo para remplazar por células sanas a las dañadas por diversos procesos en determinados tejidos. Las medidas terapéuticas empleadas pueden incluir trasplante de células madre, el uso de moléculas solubles, terapia génica e ingeniería de tejidos. En la actualidad, el método más empleado es el trasplante de células madre adultas. Sin embargo, todavía no se conocen bien los mecanismos mediante los cuales las células trasplantadas podrían mejorar o promover la regeneración de los tejidos. Para explicar estos mecanismos se han sugerido varias hipótesis, que incluyen la transdiferenciación celular, la fusión de células y los efectos secundarios a la liberación por las células de diferentes moléculas solubles con acciones específicas; además de los efectos autocrinos y paracrinos que pueden tener estos factores solubles se sugiere la existencia también de una acción telecrina. Probablemente se ejecute más de uno de estos mecanismos.
Regenerating medicine is a branch of Medicine very developed in past years. Advances in this field have been closely linked with the new knowledge achieved on stem-cells and its ability to become in cells of different tissues. This type of medicine is based on the behaviors adopted by organism to substitute those damaged cells by the healthy ones by different processes in specific tissues. Therapeutic measures used may include the stem-cell transplantation, the use of soluble molecules, genic therapy and tissues engineering. Nowadays, the more used method is the adult stem-cells. However, is not well known the mechanisms by which the transplanted cells could to improve or to promote the tissue regeneration. To explain these mechanisms some hypotheses has been proposed including the cellular trans-differentiation, cells fusion, and the effects secondaries to cells release by cells of different soluble molecules with specific actions; in addition to the autocrine and paracrine effects that may have these soluble factors, it is suggested too the existence of a telecrine action. It is probable that more than one of these mechanisms be executed.
Résumé
Objective To evaluate the effects of recombinant human bone morphogenetic-2-polylactide sustained release nanospheres (rhBMP-2-PLA-Ns) on cultured rabbit osteoblasts in vitro. Methods Rabbit osteoblasts were cultured in vitro, and rhBMP-2-PLA-Ns was added into the medium of the third generation of rabbit osteoblasts. The expression of the proliferating cell nuclear antigen (PCNA) was examined by immunofluoreacence staining, and the formation of tuberculums observed with alizarin red staining. Western blot was used to detect the effects of rhBMP-2-PLA-Ns on the expression of vascular endothelial growth factor (VEGF), which was compared with that in rhBMP-2 group and blank group. Results There was no significant difference in the number of osteoblasts with positive PCNA expression among three groups five days later. Ten days later, the number of osteoblasts with positive PCNA expression in rhBMP-2-PLA-Ns group was significantly higher than that in rhBMP-2 group and blank group, which indicated that rhBMP-2-PLA-Ns could enhance the expression of PCNA. Compared with rhBMP-2 group and blank group, rhBMP-2-PLA-Ns could significantly enhance the formation of tuberculums, with statistical difference (P<0.05). The expression of VEGF was detected in all three groups, and the level of the VEGF expression in rhBMP-2-PLA-Ns group was significantly higher than that in the other 2 groups (P<0.05). Conclusion The biological activity of rhBMP-2-PLA-Ns is superior than that of rhBMP2, and rhBMP-2-PLA-Ns can promote the proliferation, mineralization of osteoblasts and the secretion of VEGF, which has a better prospect in facilitating traumatic bone healing.