Mice and Materials

Female C57BL/6 mice (8 to10 weeks old) were purchased from Japan SLC (Hamamatsu, Japan). Animals were maintained according to guidelines for the ethical use of animals in research at Hiroshima University. VEGF-siRNA (sense strand, 5′-CGAUGAAGCCCUGGAGUGCTT-3′; antisense strand, 5′-GCACUCCAGGGCUUCAUCGTT-3′) and non-target siRNA (sense strand, 5′-UACUAUUCGACACGCGAAGTT-3′; antisense strand, 5′-CUUCGCGUGUCGAAUAGUATT-3′) were purchased from Hokkaido System Science (Sapporo, Japan). Chitosan (molecular weight [MW] 2,000–5,000, water-soluble; Wako Pure Chemical Industries, Osaka, Japan), D-(-)-mannitol (Wako Pure Chemical Industries) and L-leucine (Sigma-Aldrich, St. Louis, MO, USA) were used as a non-viral vector and excipient, respectively.