BACKGROUND: To investigate the effects of the c-kit blocker imatinib mesylate (Glivec) on the bladders of animals with suprasacral cord injury (SSCI) and sacral cord injury (SCI). MATERIALS AND METHODS: We randomized 60 female Sprague-Dawley rats into control, sham, SSCI (T8/9 transection), and SCI (S1-3 transection) groups. Six weeks later, we evaluated the effects of stepwise Glivec administrations on urinary bladder contraction using cystometry and the detrusor strip stretch-test. We investigated spontaneous calcium transients of kit-positive interstitial cells of Cajal (ICCs) with the preloaded Ca(2+) indicator fluo-3AM. The expression levels of c-kit and the number of ICCs in those bladders were determined using Western blot and fluorescence staining analyses, respectively. RESULTS: Bladder capacity and compliance were decreased in SSCI bladders and increased in SCI bladders (P<0.05). The amplitude and frequency of spontaneous contractions of detrusor strips, the frequency and relative fluorescence intensity of the spontaneous Ca(2+) waves, and c-kit expression in the bladder were significantly increased in the SSCI group and decreased in the SCI group compared with the control and sham groups (P<0.05). The dose-dependent effects of Glivec also confirmed consistent functional variations in bladder activity. CONCLUSIONS: The expressions and effects of Glivec were enhanced in SSCI bladders and inhibited in SCI bladders, which may indicate potential roles of ICCs for the c-kit signaling pathway in the pathogenesis of SSCI and SCI bladder.
BACKGROUND: To investigate the effects of the c-kit blocker imatinib mesylate (Glivec) on the bladders of animals with suprasacral cord injury (SSCI) and sacral cord injury (SCI). MATERIALS AND METHODS: We randomized 60 female Sprague-Dawley rats into control, sham, SSCI (T8/9 transection), and SCI (S1-3 transection) groups. Six weeks later, we evaluated the effects of stepwise Glivec administrations on urinary bladder contraction using cystometry and the detrusor strip stretch-test. We investigated spontaneous calcium transients of kit-positive interstitial cells of Cajal (ICCs) with the preloaded Ca(2+) indicator fluo-3AM. The expression levels of c-kit and the number of ICCs in those bladders were determined using Western blot and fluorescence staining analyses, respectively. RESULTS: Bladder capacity and compliance were decreased in SSCI bladders and increased in SCI bladders (P<0.05). The amplitude and frequency of spontaneous contractions of detrusor strips, the frequency and relative fluorescence intensity of the spontaneous Ca(2+) waves, and c-kit expression in the bladder were significantly increased in the SSCI group and decreased in the SCI group compared with the control and sham groups (P<0.05). The dose-dependent effects of Glivec also confirmed consistent functional variations in bladder activity. CONCLUSIONS: The expressions and effects of Glivec were enhanced in SSCI bladders and inhibited in SCI bladders, which may indicate potential roles of ICCs for the c-kit signaling pathway in the pathogenesis of SSCI and SCI bladder.