Abstract： Objective To investigate the effects of shRNA-TGF-β_1 plasmid on extracellular matrix synthesis of rat renal allograft.Methods shRNA-TGF-β_1 was constructed.The donor's kidney resected from SD rats was put in 4℃ heparin saline in order to get enhanced ischemiareperfusion injury.The donor's kidney was transplanted to the Wistar rat after removing its left kidney,and transfected with the plasmid using renal gene transfection technology based on the hydromechanics.The recipients were divided into four groups:group T(plasmid group)injected with shRNA-TGF-β_1;group H(vacant plasmid group)injected with vacant plasmid;group Y(simply transplantation group) injected with no plasmid;group J (sham-operated group) only removing the right kidney with no transplantation.Transplanted kidneys and blood samples were collected at the first,second and third month after transplantation.The expression levels of TGF-β_1 and type Ⅰ collagen mRNA and protein were detected by RT-PCR and Western blot respectively.Immunohistochemical staining was used to assess the tissue location of typeⅠcollagen,and the fibrosis degree was assessed by Masson staining.Results A small amount of TGF-β_1 mRNA was detected in group J,but great amount in groups H and Y.At the first month,TGF-β_1 mRNA expression in group T was significantly lower than in other groups.Although its expression was increased with the time,but still significantly lower than in groups H and Y.Type Ⅰ collagen mRNA expression in group T was lower than in groups H and Y.The protein expression of type Ⅰ collagen was similar to its mRNA expression in all groups, mainly located at cortical tubules and medulla mesenchyme,and less at glomerulus in groups H and Y.The fibrosis in group T was significantly milder than in groups H and Y.Conclusion The shRNA-TGF-β_1 plasmid could inhibit the expression of TGF-β_1 and reduce the synthesis of extracellular matrix,which could prevent fibrosis of renal allograft to varying degrees.