animal tissue article controlled study nonhuman 456 priority journal 352 Animals 350 animal experiment 299 male 217 female 181 rat 172 mouse 171 Male 164 animal cell 162 animal model 160 Mice 150 Female 149 Rats 141 protein expression 118 enzyme activity 99 unclassified drug 90 Animalia 87 Rats, Sprague-Dawley 83 messenger RNA 53 animal 52 immunohistochemistry 49 Humans 48 Mice, Inbred BALB C 48 signal transduction 47 metabolism 46 Immunohistochemistry 45