In comparison with normal control rats, those with PFD displayed a notable decrease in void volume (NC: 1.19 ± 0.07 mL; Vehicle: 0.57 ± 0.08 mL; Exo: 0.78 ± 0.09 mL; TNF‐Exo: 1.02 ± 0.11 mL; both p < 0.001 for Exo and TNF‐Exo groups vs. Vehicle group) (Figure 2B) and bladder void pressure (NC: 91.35 ± 9.14 cm water; Vehicle: 46.85 ± 8.25 cm water; Exo: 63.84 ± 10.35 cm water; TNF‐Exo: 82.35 ± 8.20 cm water; p = 0.0048 for Exo vs. Vehicle, and p < 0.001 for TNF‐Exo vs. Vehicle) (Figure 2C), indicating the successful construction of the rat PFD model. This evidence concerns the gene TNF and polyostotic fibrous dysplasia.