The present study determines whether the in vivo injection of TGFβ1 and CTGF mediated by AAV2 to transfect nucleus pulposus cells in degenerative lumbar discs can reverse the biological effects of rhesus lumbar disc degeneration. A total of 42 lumbar discs obtained from six rhesus monkeys were classified into three groups: experimental group, control group, and blank group. Degenerative lumbar discs were respectively injected with double gene-transfected human nucleus pulposus cells using minimally invasive techniques. Immumohistochemical staining, RT-PCR, and western blot were performed to observe the biological effects of double genetransfected human nucleus pulposus cells in degenerative lumbar discs on rhesus lumbar disc degeneration. At 4, 8, and 12 weeks after the transplantation of nucleus pulposus cells, the expression levels of TGF-ß1, CTGF, proteoglycan mRNA, and type-II collagen were detected by RT-PCR. The values of immumohistochemical staining and RT-PCR in the experimental group increased at 8 weeks, decreased with time at 12 weeks, and remained greater than the values in the control group, and the differences were statistically significant (P < .05). The western blot revealed that the values in the experimental group decreased with time, but remained greater than those in the PBS control group and blank control group, and the differences were statistically significant (P < .05). The double gene-transfection of human nucleus pulposus cells in degenerative lumbar discs mediated by rAAV2 can be continuously expressed in vivo after transplantation in lumbar discs of rhesus monkeys, and promotes the synthesis of proteoglycan and type II collagen, achieving the treatment purpose. K E Y W O R D S

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