Abstract:

Objective To investigate the inhibitory effect of local application of small interfering RNA (siRNA) targeting tumor necrosis factor-α (TNF-α) on wear debris-induced aseptic inflammation. Methods Recombinant lentivirus vector was constructed, and a siRNA targeting TNF-α and a missense siRNA were designed. Air pouches were established and stimulated by polymethylmethacrylate (PMMA) particles for aseptic inflammation. Mice were randomly divided into 3 groups, with 12 mice in each group, and TNF-α siRNA (TNF-α group), missense siRNA (MS group) and PBS (control group) were locally injected into pouches respectively. Mice in each group were sacrificed on the 14th day and 28th day after lentivirus transfection, with 6 rats on each day, and pouch homogenates were obtained. The expression of TNF-α, IL-1β and IL-6 mRNA in pouches was detected by Real-Time PCR, the content of TNF-α protein was determined by ELISA, the thickness of pouch membrane was measured by histological analysis, inflammatory cell counting was performed, and intensity and distribution of green fluorescent protein (GFP) were quantitatively analysed by in vivo bioluminescence imaging. Results The transfection of lentivirus-mediated TNF-α siRNA in vivo significantly decreased the expression of TNF-α, IL-1 and IL-6 mRNA and the content of TNF-α protein in TNF-α group (P<0.01). Histological analysis revealed less inflammatory responses (thinner pouch membrane and decreased cellular infiltration) in TNF-α group (P<0.05 or P<0.01). In vivo bioluminescence imaging indicated the expression of GFP in pouches was locally restrained, and the fluorescence quantity in TNF-α group and MS group was about 5 times higher that in control group. Conclusion Local application of TNF-α siRNA may effectively inhibit wear debris-induced aseptic inflammation, with no systemic adverse effects.

Key words: aseptic inflammation, lentivirus, small interfering RNA, tumor necrosis factor-α