Delaying Of Denervated Muscle Atrophy In Rat By Means Of Gene Downregulation 0f FOXO3a By RNAi

Objective:To Explore the effect of delaying atrophy of rat denervted skeletal muscles by RNAimediated gene downregulation 0f FOXO3 a.Methods:Fourty SD rats were randomly divided control group and experimental group.Models of extensor digitorum longus muscle denervation atrophy were established at the right lower limb by cutting sciatic nerve. Denervated extensor digitorum longus muscles of experimental groups were administered with 50 μ L of recombinant lentivirs vector carrying FOXO3 a. 50μL lenti—GFP solution was administered into Denervated extensor digitorum longus muscles of control groups.One and 3 weeks after the transfection,the right intact extensor digitorum longus muscles of 3 rats of each group and timepoint were excised to observe green fluorescent under fluorescent microscope. The right intact extensor digitorum longus muscles of 6 rats of each group and timepoint were excised to observe ultrastructure of muscle cells under the transmission electron microscope and measure the total protein content of extensor digitorum longus,muscle wet weight preservation rate,total protein content of extensor digitorum longus and muscle fiber cross-sectional.Results:One and 3 weeks after transfection strong GFP green fluorescent was observed in the extensor digitorum longus muscles of both Groups.One weeks after transfection, wetweight preservation rate,total protein content and muscle fiber cross-seetional area of the denervated muscles in the experimental group were,( 90.87±1.56)%,( 93.20±1.33)(mg/m L) and(937.63.42±17.63)μ㎡ respectively,being obviously greater than those parameters of the control group,which were(77.73±2.21)%,( 74.74±1.45)(mg/m L)and(721.50±14.40)μ㎡ respectively(all P<0.01). After 1 and 3 weeks RT-PCR showed significantly reduced expression of gene FOXO3 a in the experimental group compared with the control group(P<0.01).After 3 weeks,the above-mentioned parameters were(86.69±1.31)%,(80.39±2.34)(mg/m L) and(843.10±16.44)μ㎡ respectively in the experimental group,being obviously higher than those parameters of the control group which were(53.42±2.01)%,(65.22±2.72)(mg/m L) and(633.90±12.90)μ ㎡ respectively(all P<0. 01). The ultramicrostructure of myocyte show that the regressive cell nucleus of the experimental group was significantly less than those in the control group.Conclusions:FOXO3a si RNA recombinant lentivirus can achieve high transfection efficiency in rats and efficaciously inhibit the expression of FOXO3 a gene. Gene downregulation 0f FOXO3 a by RNAi can delay atrophy of rat denervted skeletal muscles.