Kit comprises a skin model and a composition comprising a double stranded RNA oligonuleotide associated with a cation particle having a size of =1 mu m and zeta potential of 10-80 mV, preferably surface-active micelles, polymer block micelles, nonionic or cationic surface-active liposomes, niosomes, oleosomes, particles of nanoemulsions, nanocapsules or (in)organic particles. An independent claim is included for a process of preparing a skin model comprising administering the composition in the culture medium of the model.