animal cell controlled study nonhuman protein expression Animals 396 priority journal 368 article 364 mouse 274 Mice 250 animal experiment 226 animal tissue 169 female 168 unclassified drug 167 human 154 Humans 153 animal 153 animal model 146 Female 143 male 143 metabolism 142 Male 117 human cell 112 messenger RNA 112 protein function 107 rat 106 cell proliferation 99 signal transduction 99 Article 98 apoptosis 88 Rats 85