Animals animal cell 143 nonhuman 143 animal 134 controlled study 127 Article 122 animal experiment 97 mouse 80 animal tissue 71 male 69 metabolism 69 Mice 66 animal model 57 human 56 Humans 54 female 52 unclassified drug 52 Male 44 rat 42 genetics 38 drug effect 37 in vitro study 37 protein expression 36 Rats 34 physiology 32 Female 31 gene expression 31 adult 30 in vivo study 29 human cell 27