ABSTRACT
@#Objective To investigate the biological distribution of B1 antisense RNA(Blas RNA) of mouse short interspersed nuclear element in blood and tissues of normal mice after vein injection and detect the cell uptake efficiency of B1 as RNA using cultured normal mouse embryo cells after transfection.Methods Six 8～12-week-old BALB/c mice,three males and three females,were injected with 20 μg Blas RNA via tail vein,and blood samples were collected at different times after injection.54 BALB/c mice of 8～12-weeks were injected with 20 μg Blas RNA via tail vein,of which six mice,three males and three females,were euthanized at different times after injection,and various tissues,including the heart,liver,spleen,lung,kidney and thymus were harvested.Blas RNA was transfected into cultured mouse embryonic cells,and a certain amount of cells were taken at different time after transfection.The biological distribution of B1as RNA in mouse blood and different tissues and the persistence of Blas RNA in cultured embryo cells were detected by RT-qPCR.30naturally senescent BALB/c mice(≥ 14 months old) were divided into three groups:treatment group(20 μg Blas RNA injected via tail vein,once a week),irrelevant RNA control group(20 μg LacZ3F3R RNA injected via tail vein,once a week) and saline control group(injected with the same volume of saline),with 10 mice in each group,and a young control group(normal young 8～12-week-old BALB/c mice,five males and five females) was set.Four weeks after administration,mice in each group were euthanized,the liver tissues were taken,and the expression levels of aging-related genes(Sirtl,p21,p16~(Ink4a),p15~(Ink4b),p19~(Arf)) were detected by RT-qPCR.Results After tail vein injection,Blas RNA was available in the blood of mice for approximately 30 min,persisted for approximately 2～4 h in most detected tissues and persisted for approximately 48 h in lungs.The efficiency of cellular uptake of Blas RNA was approximately 400 molecules per mouse embryo culture cell 45 min after transfection with B1as RNA.Compared with the saline control group,Blas RNA treatment significantly down-regulated the mRN A expression of p21,p16~(In4a),p15~(In4b) and p19~(Arf) genes(t=10.01,4.461,4.420 and 5.309 respectively,each P <0.05),and significantly up-regulated the mRNA expression of Sirt1 gene(t=4.579,P <0.05).Conclusion Blas RNA was efficiently taken up by cells after transfection.After intravenous injection,Blas RNA stayed in the blood and tissues for a certain period of time and regulated the expression of aging-related genes in aged mice so as to make them approach to the expression level of young normal mice.