Figure 3.

In vivo, noninvasive methods to evaluate cancer-induced bone pain (CIBP). (A) Incapacitance tester: cancer cells are intratibially injected monolaterally, and after an experiment-specific timeframe the animal is placed on an incapacitance tester. This is a device which features 2 scales, that are able to discriminate weight distribution between the 2 hindlimbs, when the animal is stood up at an incline (as visible from A, upper panel). In normal conditions, rodents will tend to distribute the weight evenly between the 2 limbs, but when one of them experiences CIBP, mice will relieve them from some of their body weight, reducing the % of weight bore by that limb. (B) Spontaneous deambulation test: mice are acclimated in a 45 × 45 × 45 cm arena 3 times the week before the cancer cells inoculation to establish a baseline. On the third test, the trajectory of the mouse is recorded and quantified over a specific timeframe (e.g., 10 min), to assess the distance the mouse is willing to walk voluntarily, without external stimulation. Cancer cells are then injected monolaterally (e.g., intratibially) and after an appropriate time (e.g., T₁₄ and T₂₁ days), mice will start showing a decrease in spontaneous ambulation, which is mostly due to CIBP. It is also possible to review the mouse behaviour to assess rearing behaviour and limb usage if a video recording device is used for the test.