ABSTRACT
Objective To investigate the difference between histopathological changes of brain white matter in low-density lipoprotein receptor (LDLR) homozygous mutation rats with hypercholesterolemia and wild-type rats.Methods Thirty LDLR-/-rats and 28 wild-type rats were selected.Plasma cholesterol levels were measured by enzyme-linked immunosorbent assay at 15,18 and 26 weeks old respectively.The axonal structure of the corpus callosum area was observed by transmission electron microscopy.The myelin basic protein (MBP) of the corpus callosum area was quantitatively analyzed by Western blotting.In addition,at 26 weeks old,the myelin sheaths were stained by fast blue staining.The expression level of MBP in white matter was further detected by immunofluorescence staining,and the morphological changes of glial cells were observed.Results Compared with the wild-type rats,the plasma cholesterol concentration in LDLR-/-rats increased significantly,and it could be as high as 3.3 times at 26 weeks.The results of electron microscopy showed that the LDLR-/-rats had axonal injury at 15 weeks and aggravated gradually over time.At 26 weeks,Western blot analysis of the LDLR-/-rats showed that the MBP expression level of the corpus callosum area decreased significantly.Fast blue staining showed loosening of nerve fibers,diffuse vacuole formation,and myelinated nerve fiber loss in the corpus callosum area.In addition,it was also found that the number of oligodendrocytes in LDLR-/-rats was significantly reduced,and large numbers of astrocytes and microglia were activated.Conclusions LDLR-/-rats will have spontaneous hypercholesterolemia.Axonal injury,demyelination,decreased oligodendrocytes,as well as the abnormal activation of astrocytes and microglia are present in the early adult brain white matter area.
ABSTRACT
BACKGROUND:Mesenchymal stem cells from transgenic animals carry green fluorescent protein that can be stably expressed in viable cells and can be used to rapidly screen modified cells in comparison with traditional virus and plasmids. OBJECTIVE:To study the biological features of bone marrow derived stromal cells from transgenic rats with green fluorescent protein gene. METHODS:Bone marrows were isolated from the bilateral long bones of 2-week-old transgenic rats with green fluorescent protein gene, and cultivated in conditioned culture medium to obtain bone marrow mesenchymal stem cells with green fluorescent protein gene. The passage 5 bone marrow mesenchymal stem cells with green fluorescent protein gene were analyzed by flow cytometry to detect cellsurface molecules, and were induced in calcium or adipogenic induction medium. After calcium induction, the alizarin red staining was performed to test the formation of calcium concentration. After adipogenic induction, bone marrow mesenchymal stem cells were detected with oil red O staining. RESULTS AND CONCLUSION:Bone marrow mesenchymal stem cells, stably expressing green fluorescent protein gene, were obtained successful y from the transgenic rat with green fluorescent protein gene. The cells expressed CD90, CD105 strongly, but did not express or weakly expressed CD14 andCD45. After 3 weeks of calcium induction, jacinth calcium salts could be detected in the cells by alizarin red staining. At 3 weeks of adipogenic induction, the cells showed positive oil red O staining. The green fluorescent protein gene, as report gene, exerts no effect on the cellsurface molecules and multilineage potential of bone marrow mesenchymal stem cells, which can be used as an efficient tracer.