Altered bladder function in elastin‐deficient mice at baseline and in response to partial bladder outlet obstruction

Abstract

OBJECTIVE To examine functional and molecular changes of the bladders from elastin-haploinsufficient mice (Eln+/−) at baseline as well as in response to partial bladder outlet obstruction (pBOO). MATERIALS AND METHODS Female Eln+/− and wild type (Wt) mice (3–4 months old) were studied. The bladder elastin content was quantified by measuring desmosine. Mice were divided into two groups to undergo surgery to create pBOO or to undergo sham surgery. Three days after surgery, bladder function was evaluated by in vivo cystometry, and the contractile response of bladder strips exposed to electrical field stimulation (EFS) and carbachol was examined by ex vivo myography. RESULTS The Eln+/−-sham mice had a 33.6% decrease in bladder elastin compared with Wt-sham mice. Cystometry showed significantly decreased bladder compliance and capacity in Eln+/−-sham vs Wt-sham mice; pBOO increased bladder compliance and capacity to a greater extent in Eln+/− mice compared with Wt mice. Bladder strips from Eln+/−-sham mice showed a significantly heightened contractile response to both EFS and carbachol compared with Wt-sham mice. A significantly increased contractile response to carbachol was detected in Wt-pBOO vs Wt-sham but not between Eln+/−-pBOO and Eln+/−-sham mice. CONCLUSION The results that elastin-deficient mice had decreased bladder compliance and capacity and increased bladder contractility; and that Wt-pBOO mice showed an enhanced contractile response to carbachol, but Eln+/−-pBOO mice did not, suggest that elastin is critical for normal bladder function and is involved in bladder response to pBOO.

Combinational effects of muscarinic receptor inhibition and β3‐adrenoceptor stimulation on neurogenic bladder dysfunction in rats with spinal cord injury

“…These results suggest the usefulness of the combination therapy for SCI‐induced neurogenic bladder dysfunction over the monotherapy. Previous studies indicated that abnormal deposition of type 3 collagen and decreased elastin deposition results in low bladder compliance . In vehicle‐treated SCI rats (group A) of this study, mRNA levels of type 3 collagen and the total collagen content in the bladder were increased compared to normal spinal intact rats.…”

“…Previous studies indicated that abnormal deposition of type 3 collagen and decreased elastin deposition results in low bladder compliance. [11][12][13][14] In vehicle-treated SCI rats (group A) of this study, mRNA levels of type 3 collagen and the total collagen content in the bladder were increased compared to normal spinal intact rats. The monotherapy with oxybutynin, but not mirabegron, and the combination therapy reduced the mRNA expression of type 3 collagen although the combined or monotherapy of oxybutynin and mirabegron did not affect the protein concentration or total amount of collagen in SCI rats.…”

An optimized transurethral catheterization cystometry in mice and comparison with classic suprapubic catheterization cystometry

“…For example, the COMs (bladder compliance) in one previous study of TUCC for mice, was defined as 75% of bladder capacity divided by the change in bladder pressure from the beginning of infusion to 75% of bladder capacity . In another research, it was defined as the change from baseline in infusion volume divided by the change in intravesical pressure . In our study, the COM was defined as bladder capacity divided by threshold minus basal pressure .…”

“…In order to avoid over‐distension of the bladder wall, cystometry was regularly stopped at an intravesical pressure of about 25 mmHg, 50 cmH 2 0, or others, while continuous infusing cystometry was performed for several voids in our study. Additionally, the transurethral catheter's outer diameter used in this minimally invasive TUCC was 0.41 mm, finer than previous commonly used transurethral catheter (PE10 or 24G catheter, 0.6 mm) with similar inner diameter (PUFC‐C30‐10:0.23 mm vs PE10 or 24G catheter: 0.28 mm). In consideration of small volume of mice bladder, the infusing saline rate in our study was 0.6 mL/h in order to better stimulate physiologic bladder voiding.…”

“…In our study, the COM was defined as bladder capacity divided by threshold minus basal pressure . Besides, bladder pressure curves of continuous infusion cystometry did not appear in previous studies . In order to avoid over‐distension of the bladder wall, cystometry was regularly stopped at an intravesical pressure of about 25 mmHg, 50 cmH 2 0, or others, while continuous infusing cystometry was performed for several voids in our study.…”