Effectiveness of lentivirus-mediated RNA interference targeting mouse tumor necrosis factor α in vitro and in vivo

The aim of the present study was to identify the effectiveness of lentivirus-mediated RNA interference (RNAi) targeting mouse tumor necrosis factor-alpha (TNF-alpha). RNAi lentivirus was used in vitro to transfect RAW264.7 cells, and the expression of TNF-alpha, interleukin (IL)-1 beta and IL-6 mRNAs and TNF-alpha protein in RAW264.7 cells was measured by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay, respectively. In vivo, mice with collagen-induced arthritis (CIA) were injected intravenously with RNAi lentivirus, and CIA arthritis scores and the serum levels of TNF-alpha were detected. Additionally, joint tissues were subjected to pathological examination. In the cells, the expression level of TNF-alpha mRNA in the RNAi lentivirus group was 0.29 +/- 0.02, which was significantly lower than that of the lentivirus negative control (0.93 +/- 0.01; t=25.4, P<0.001). In the mice, the serum TNF-alpha level in the RNAi lentivirus group was 249.25 +/- 11.22 ng/ml, which was significantly lower than that of the negative control group (381.86 +/- 6.28 ng/ml; P<0.05). However, no difference in IL-1 and IL-6 mRNA levels was identified among the groups (t=1.00, P=0.37; t=1.22, P=0.29). The CIA arthritis score in the RNAi lentivirus group was significantly reduced compared with those in the control and negative control groups (P<0.05). Furthermore, the arthritis scores in the RNAi lentivirus and positive control groups continued to decrease for 2 weeks, and the serum TNF-alpha levels in the RNAi lentivirus and positive control groups were 31.58 +/- 2.18 and 35.21 +/- 2.25 pg/ml, which were significantly lower than those in the negative control group (46.62 +/- 3.02 pg/ml; P<0.05). Thus, targeting of the TNF- gene in mice via lentivirus-mediated RNAi in vitro and in vivo achieved TNF-alpha gene downregulation, which indicates that lentivirus-mediated RNA interference may be an effective form of gene therapy against rheumatoid arthritis.