Figure 3.

In vivo delivery of siRNA to liver in rodents. (a) Mice (n = 3) received two daily i.v. injections of different lipidoid formulations of siRNA at a dose of 2.5 mg/kg. Factor VII protein levels were quantified 24 h after the second administration. (b) Simultaneous silencing of two genes in vivo in mice. Mice (n = 3) received a single i.v. bolus injection of a 98N12-5(1)-formulated 1:1 (wt/wt) mixture of siFVII and siApoB at 10, 6 or 4 mg/kg (5, 3 or 2 mg/kg of each siRNA). For comparison, control animals received PBS or lipidoid-formulated siFVII alone or lipidoid-formulated siApoB alone at 5, 3 or 2 mg/kg. Forty-eight hours after administration animals were killed and livers were harvested. Liver mRNA levels of Factor VII or ApoB (normalized to GAPDH) were determined by branched DNA assay. (c–e) Rats (n = 4) were injected with lipidoid-formulated siRNA at 1.25, 2.5, 5 and 10 mg/kg. Animals were bled and killed 48 h after administration; shown are liver mRNA levels (c), serum Factor VII protein levels (d) and prothrombin time (e). (f) Durability of silencing in rats. Rats (n = 5) received a single i.v. administration of lipidoid-formulated siRNA at 5 mg/kg. Animals were bled at various time points after administration and serum Factor VII protein levels were quantified. Data points represent group mean ± s.d. Data points marked with asterisks are statistically significant relative to control treated groups (*, P < 0.05; **, P < 0.005; ***, P < 0.001; t-test, single-tailed).