controlled study human in vitro study nonhuman priority journal Animals 65 animal cell 60 Humans 59 animal experiment 56 mouse 54 human cell 51 animal model 48 Mice 47 in vivo study 46 article 43 unclassified drug 41 animal 40 protein expression 40 metabolism 36 Article 34 female 32 male 32 animal tissue 30 cell proliferation 28 Female 26 Cell Proliferation 22 Male 20 genetics 20 pathology 18 gene expression 16