HCV Transgene Expression Inhibition

To provide an immunocompetent model for inhibition of HCV protein expression, a mouse strain harbouring an HCV transgene was generated via a Cre/loxP switching system37 (link). We bred CN2-29 transgenic mice, which carry an HCV transgene (nt. 294–3435), with Mx1-Cre transgenic mice, which express Cre recombinase in response to interferon (IFN)-α or a chemical inducer of IFN-α, poly(I:C). Following poly(I:C) injection, the HCV transgene was rearranged, and HCV sequences were expressed in the livers. In this model, HCV structure proteins are expressed in the liver within 7 days after poly(I:C) injection. Male CN2-29 trasgegenic mice (8–9 week-old) were injected intraperitoneally with 0.3 mL of 1 mg/mL poly(I:C) solution [in PBS (-)]. At 6 months after the poly(I:C) injection, the CN2-29 mice were administrated intravenously twice with the siRNA-MEND complex solution [1 mg/mL in PBS(-)] via orbital sinus at day 0 and day 2. The mice were sacrifice under anesthesia with ketamine/xylazine 2 days after the second siRNA-MEND administration. Livers were removed, fixed in 10% buffered formalin, and embedded in paraffin. Section (4 μm) were stained with hematoxylin and eosin, and observed using ZEISS Axio Imager A2 upright microscope (Carl Zeiss MicroImaging, Inc, Germany).