BERK and hBERK1 mice show deep tissue and mechanical hyperalgesia. All data are shown as mean ± SEM from 4 to 6 mice with 3 observations per mouse. Measurements were made on each mouse on 3 consecutive days. (A) Grip force measurements from age-matched BERK (▲) and HbA-BERK (▵) mice. A lower grip force indicates increased deep tissue hyperalgesia. *P < .05 versus age-matched BERK. #P < .01 versus 3-month-old BERK. (B) Paw withdrawal threshold (50%) to von Frey monofilaments in 10-month-old BERK and HbA-BERK mice. *P < .05. (C) PWF with a von Frey monofilament in BERK (▲) and age-matched HbA-BERK (▵). A higher PWF indicates increased nociception. *P < .05 versus age-matched HbA-BERK. #P < .01 versus 3-month-old BERK. (D) Grip force measurements from 12-month-old male hBERK1 mice compared with age- and sex-matched HbA-BERK mice. A lower grip force indicates increased deep tissue hyperalgesia. **P < .01. (E) Effect of age and sex on grip force in hBERK1 mice (M indicates male; F, female). *P < .05, **P < .01 between the indicated conditions. (F) Paw withdrawal threshold (50%) using von Frey monofilaments in 9- to 10-month-old female hBERK1 mice compared with age- and sex-matched HbA-BERK mice. A lower threshold is indicative of increased sensitivity to nociceptive stimuli. *P < .05. (G) PWF with von Frey monofilaments in male hBERK1 mice (■) compared with HbA-BERK mice (□) at different ages. A higher PWF reflects increased nociception. **P < .01, significant differences (15-month vs 5-month hBERK1). #P < .01, significant differences (15-month hBERK1 vs 15-month HbA-BERK).