In a representative animal study, published earlier this year, lab mice ran on a wheel or treadmill to gauge their fitness.
In this set-up, mice ran on a treadmill receiving sips of water as a reward, while different sounds, scents, visual cues, and textures of the treadmill belt simulated two similar but not identical environments.
Briefly, mice ran on a transparent flat treadmill at a specific speed, while a video camera captured ventral images.
We had previously identified C3H/HeJ inbred mice as low-active and C57L/J inbred mice as high-active [ 10] with the C57L/J mice running, on average, 271% farther on a daily basis than the low-active C3H/HeJ mice.
Distinctively from the other datasets, a difference between centres was observed when mice ran on the standard wheel, but not the complex wheel [first week: F 1,51)=8.804, P=0.005; second week: F 1,51)=5.589, P=0.02; third week: F 1,50)=0.631, n.s.].
As shown in Fig 1A, when treadmill speed was progressively increased in the intense anaerobic exercise paradigm, 65-day-old SOD1G86R mice had significantly poorer performance than their WT littermates; SOD1G86R mice ran on the treadmill for an average of 13.50 min (median at 14.33), while their WT littermates spent an average of 15.78 min (median at 15.50) on the treadmill (Fig 1B).
Tmub1 KO mice appeared normal in terms of weight, length and in a battery of physiological and metabolic assays (data not shown) routinely run on all mice generated with genetic deficiencies at Lexicon Pharmaceuticals [16].
Thus, even in mice running to exhaustion on the incremental enclosed metabolic treadmill, continuous reliable measurement of cardiovascular function can be achieved.
On a treadmill, the treated mice ran for an hour on average, compared with only 35 minutes for untreated ones.
