Expression and function of transforming growth factor-β isoforms and cognate receptors in the rat urinary bladder following cyclophosphamide-induced cystitis

Abstract

Numerous proinflammatory cytokines have been implicated in the reorganization of lower urinary tract function following cyclophosphamide (CYP)-induced cystitis. The present study investigated the functional profile of three pleiotropic transforming growth factor-β (TGF-β) isoforms and receptor (TβR) variants in the normal and inflamed (CYP-induced cystitis) rat urinary bladder. Our findings indicate that TGF-β (1, 2, and 3) and TβR (1, 2, and 3) transcript and protein expression were regulated to varying degrees in the urothelium or detrusor smooth muscle following intermediate (48 h; 150 mg/kg ip) or chronic (75 mg/kg ip; once every 3 days for 10 days), but not acute (4 h; 150 mg/kg ip), CYP-induced cystitis. Conscious, open-outlet cystometry was performed to determine whether aberrant TGF-β signaling contributes to urinary bladder dysfunction following intermediate (48 h) CYP-induced cystitis. TβR-1 inhibition with SB505124 (5 μM) significantly (p ≤ 0.001) decreased voiding frequency and increased bladder capacity (2.5-fold), void volume (2.6-fold), and intercontraction intervals (2.5-fold) in CYP-treated (48 h) rats. Taken together, these results provide evidence for 1) the involvement of TGF-β in lower urinary tract neuroplasticity following urinary bladder inflammation, 2) a functional role of TGF-β signaling in the afferent limb of the micturition reflex, and 3) urinary bladder TβR-1 as a viable target to reduce voiding frequency with cystitis.

Role of c-Jun N-Terminal Kinase (JNK) Activation in Micturition Reflexes in Cyclophosphamide (CYP)-Induced Cystitis in Female Rats

“…); (3) every third day over a 10 day period (75 mg/kg, i.p.) (Arms et al, 2010; Arms et al, 2013; Gonzalez et al, 2013). Control animals received no treatment.…”

“…Rats were anesthetized with isoflurane (3-4%), a lower midline abdominal incision was made, and polyethylene tubing (PE-50, Clay Adams, Parsippany, New Jersey) was inserted into the bladder dome and secured with a nylon purse-string sutures (6-zero) (Schnegelsberg et al, 2010; Gonzalez et al, 2013; Merrill et al, 2013b). The end of the PE tubing was heat flared, but the catheter did not extend into the bladder body or neck and it was not associated with inflammation or altered cystometric function (Schnegelsberg et al, 2010; Gonzalez et al, 2013, Merrill et al, 2013b).…”

“…The end of the PE tubing was heat flared, but the catheter did not extend into the bladder body or neck and it was not associated with inflammation or altered cystometric function (Schnegelsberg et al, 2010; Gonzalez et al, 2013, Merrill et al, 2013b). The distal end of the tubing was sealed, tunneled subcutaneously and externalized at the back of the neck out of reach of the animal (Schnegelsberg et al, 2010; Gonzalez et al, 2013; Merrill et al, 2013b). Abdominal and neck incisions were closed with nylon sutures (4-zero).…”

“…The effects of JNK phosphorylation blockade with SP600125, a selective inhibitor of phosphorylation of JNK (Bennett et al, 2001), on urinary bladder function in CYP-treated (4 hr and 48 hr; n = 6 each) rats and control rats ( n = 6 each) were assessed using conscious, open outlet, cystometry with continuous instillation of intravesical saline (Schnegelsberg et al, 2010; Gonzalez et al, 2013; Merrill et al, 2013b). For intravesical administration of SP600125, rats were anesthetized with 2% isoflurane and SP600125 (<1.0 ml) was injected through the bladder catheter; the animals were maintained under anesthesia to prevent expulsion of SP600125 via a voiding reflex.…”

“…Altered visceral sensations from the urinary bladder (i.e., pain at low or moderate bladder filling) that accompany BPS/IC (Driscoll and Teichman, 2001; Hanno and Sant, 2001; Sant and Hanno, 2001; Quillin and Erickson, 2012) may be mediated by many factors including changes in the properties of peripheral bladder afferent pathways such that bladder afferent neurons respond in an exaggerated manner to normally innocuous stimuli (allodynia). These changes may be mediated, in part, by inflammatory changes in the urinary bladder including neurotrophins (Schnegelsberg et al, 2010), cytokines (Gonzalez et al, 2013), chemokines (Arms et al, 2010; Arms et al, 2013) and neuropeptides (Vizzard, 2001; Merrill et al, 2013a). We have previously characterized the involvement of the classical mitogen activated protein (MAP) kinase (ERK1/2) in micturition reflexes in the context of urinary bladder inflammation (Corrow and Vizzard, 2007; 2009).…”