We conducted a Western blot analysis to measure the expression of BDNF-TrkB signaling in the SDH, and found that BDNF, TrkB, and p-TrkB were upregulated on days 8, 12, and 17 after the first CYP injection in the group with cystitis (Fig. 1b–d). Here, NTRK2 is linked to cystitis.