Fig. 1 |. Analysis of rodent use in pain studies from 1980 to 2020.

The methods and results sections of preclinical reports published in the journal Pain in the years 1980, 1990, 2000, 2010 and 2016–2020 (506 articles) were coded for a variety of terms, including ‘animal species’, ‘sex’ and ‘rodent strain’. Pain was selected as the representative journal for this analysis; however, it is recognized that the restriction of the analysis to a single journal may have implications for the generalizability of the findings to the wider pain literature. Inclusion was further restricted to studies that used inducible pain models and measured behaviours in awake non-human animals. Detailed coding methods and complete datasets are included in Supplementary methods and Supplementary data 1. a | Percentage of all studies published in Pain in the years listed that used rats or mice as the primary model organism. Between 2016 and 2020, only 4 of 320 studies analysed used non-rodent animals; dogs were used in 3 studies and pigs were used in 1 study. b | Mouse strain use in studies published in Pain between 2016 and 2020. The chart illustrates the percentage of mouse studies using each strain. c | Rat strain use in studies published in Pain between 2016 and 2020. The chart illustrates the percentage of rat studies using each strain. d | Use of male and female organisms in studies published in Pain studies between 2016 and 2020. The chart illustrates the percentage of all studies using male, female, or male and female organisms. LE, Long–Evans; NR, not reported; SD, Sprague Dawley; SW, Swiss Webster.