[Lentivirus-mediated BMP-2 overexpression plasmid transfection into bone marrow mesenchymal stem cells combined with silk fibroin scaffold for osteoblast transformation].

OBJECTIVE: To explore the effect of lentivirus-mediated BMP-2 overexpression plasmid transfection into bone marrow mesenchymal stem cells and silk fibroin scaffold on osteoblast transformation. METHODS: The lentivirus BMP-2 overexpression vector was constructed, bone marrow mesenchymal stem cells were cultured, and the combined culture system of nuclear scaffolds was constructed. Alizarin red staining and alkaline phosphatase staining were used to detect the osteogenic transformation of bone marrow mesenchymal stem cells in vitro. Ten New Zealand white rabbits, weighing 3.2 to 4.5 kg(averaging 3.9 kg), aged (2.89±0.45) years old, were selected to construct the rabbit tibial defect model by drilling a conical tibial defect (5 mm in length, 2 mm in width and 3 mm in depth) with an oral drill. The repair of the tibial defect in the animal model was observed by HE staining. The experimental group was implanted with silk fibroin scaffold + BMP-2 overexpression vector bone marrow mesenchymal stem cell complex, while the negative control group was implanted with silk fibroin scaffold+non-transfected bone marrow mesenchymal stem cell complex. RESULTS: Compared with the control group(silk fibroin scaffold+non-transfected bone marrow mesenchymal stem cells), the number of adherent cells on the surface of the scaffold in the experimental group(silk fibroin scaffold+transfected BMP-2 overexpression vector BMP-2 complex) increased significantly. Compared with the control group, the ECM secretion in the experimental group increased significantly. EDX analysis showed that the content of calcium ion was 0.22% in the control group and 0.86% in the experimental group, which showed that the ability of inducing calcium ion formation in the experimental group was stronger than that in the control group. Alizarin red staining of calcium nodules showed that there was no obvious change in the naked eye of the control group, and a small amount of calcium nodules could be seen under the microscope. In the experimental group, obvious red area staining was observed by naked eye, and a large number of calcium nodules were observed by microscopy. The results of alkaline phosphatase staining showed that there was no obvious change in the naked eye of the control group, and no obvious change in the microscopic observation. In the experimental group, purple area staining was observed by naked eyes, and ALP staining was strongly positive by microscopy. The combined culture system of silk fibroin scaffold and bone marrow mesenchymal stem cells can repair cartilage defects. The repair effect of BMP-2 bone marrow mesenchymal stem cells after transfection is obviously better than that of non-transfection group. HE staining showed that inflammatory cells decreased and scaffolds disappeared slightly in the control group. In the experimental group, inflammatory cells were significantly reduced, scaffolds disappeared and angiogenesis was observed. CONCLUSIONS: Lentivirus-mediated BMP-2 overexpression plasmid can promote BMSC to differentiate into osteocytes and secrete more extracellular matrix containing Ca²âº to promote bone defect repair.

[Spectral study of the effects of glasses lenses' color depth on stereoscopic vision].

Glasses with zero focal-length lens and different shades of red, yellow and blue were studied in terms of absorbance by UV-Vis spectral absorption method. The effect of lens with different shades of the same color on stereoscopic vision was comparatively studied from the medical view. The study has shown that, for yellow and blue lens, there is no difference in the absorbance between the deep-color and light-color lens in UV; at 550 nm, the absorbance of deep-color lens is higher than that of light-color lens. Whereas, for red lens, the absorbance of light-color lens in UV is higher, and at 550 nm, still higher than that of deep-color. Those with light-color glasses of yellow or blue have much better stereoscopic vision than those with deep-color glasses, while the case is inversed as to those wearing red glasses. The conclusion can be drawn that the effect of lens with different shades on stereoscopic vision depends on the absorbance of lens at 550 nm, and the higher the absorbance, the stronger the effect.