animal experiment article nonhuman priority journal protein expression controlled study 265 Animals 238 animal tissue 175 female 154 mouse 154 animal model 151 animal cell 142 Mice 136 Female 135 male 123 Male 97 rat 94 Rats 85 Humans 70 unclassified drug 63 human 60 messenger RNA 56 Rats, Sprague-Dawley 55 cell proliferation 55 immunohistochemistry 54 enzyme activity 48 RNA, Messenger 47 Mice, Inbred BALB C 46 apoptosis 46 human cell 45