animal experiment animal model male nonhuman controlled study 345 Animals 277 article 270 priority journal 258 mouse 248 Male 247 animal tissue 211 Mice 194 animal cell 150 female 122 protein expression 106 rat 93 Article 92 animal 83 in vivo study 73 unclassified drug 72 Rats 71 human 69 Female 67 in vitro study 64 metabolism 64 enzyme activity 59 Humans 57 human cell 47 drug effect 46 Mus 43