Compensatory regrowth of the mouse bladder after partial cystectomy

Urine-based regenerative RNA biomarkers for urinary bladder wound healing

Background: This study aimed to investigate the expression of regeneration-related genes in canine urine during bladder repair. Materials & methods: Canine urine samples were collected after partial cystectomy. Regenerative mRNA of hypoxia-inducible factor (HIF), vascular endothelial growth factor (VEGF), key stem cell transcription factors and cholinergic signals were detected. Results: HIF-1α, VEGF, CD44, IL-6 and prominin-1 expression in canine urine after partial cystectomy exhibited two similar peaks at ∼2 weeks. HIF-1α and VEGF expression were higher in the afternoon than the morning. The expression of key stem cell transcription factors and cholinergic signals also exhibited a rhythm along with bladder healing. Conclusions: The expression of HIF-1α, VEGF, key stem cell transcription factors and cholinergic signals exhibited a time curve distribution during canine bladder healing. The expression trend of some regenerative genes was similar during bladder healing, and a cooperative effect may exist.

Comparison of Intravesical Hyaluronic Acid, Chondroitin Sulfate, and Combination of Hyaluronic Acid-Chondroitin Sulfate Therapies in Animal Model of Interstitial Cystitis

PURPOSE

Three intravesical treatment agents were compared in an interstitial cystitis rat model: chondroitin sulfate, hyaluronic acid, and combined hyaluronic acid-chondroitin sulfate.

METHODS

Thirty-five female rats were divided into 5 groups: control (group I), isotonic (group II), chondroitin sulfate (group III), hyaluronic acid (group IV), and hyaluronic acid-chondroitin sulfate (group V). Chemical cystitis was induced in all experimental groups by intravesical instillation of 1 mL of hydrogen peroxide (H2O2) for 15 minutes via the transurethral route. The treatment was administered every other day for 3 sessions 2 days after inducing chemical cystitis. Groups II, III, IV, and V received 1 mL of 0.9% NaCl, 1 mL of 0.2% sodium chondroitin sulfate, 1 mL of low-molecular-weight hyaluronic acid, and 1 mL of 2% sodium chondroitin sulfate+1.6% sodium hyaluronic acid, respectively. On day 7, the animals were sacrificed and the bladders were removed for histopathological and immunohistochemical assessments.

RESULTS

Significant between-group differences were found in vascular congestion (P=0.006). The grade of submucosal edema in groups II and IV was significantly higher than in group I (P=0.006, P=0.006, respectively). In group I, the grade of granulation tissue was lower than the other 4 groups, but no significant difference was found between the remaining groups (P=0.016). Neutrophil cell infiltration was more intense in groups II and IV than in group I (P=0.006, P=0.006, respectively). Significant differences in the leukocyte and mast cell count were detected between groups II and IV (P<0.001, P<0.001, respectively). Abnormal zonula occludens-1 and uroplakin-III immunoreactivity in group II was higher than in groups I, III, or V (P=0.002, P=0.010, respectively). Interleukin-8 expression was lower in group V than in group II (P=0.001).

CONCLUSION

A single treatment of chondroitin sulfate and combined hyaluronic acid-chondroitin sulfate treatment demonstrated efficacy by suppressing inflammation and achieving improvements in the urothelium.

The Homeodomain Transcription Factor NKX3.1 Modulates Bladder Outlet Obstruction Induced Fibrosis in Mice

Fibrosis is an irreversible remodeling process characterized by the deposition of collagen in the extracellular matrix of various organs through a variety of pathologies in children, leading to the stiffening of healthy tissues and organ dysfunction. Despite the prevalence of fibrotic disease in children, large gaps exist in our understanding of the mechanisms that lead to fibrosis, and there are currently no therapies to treat or reverse it. We previously observed that castration significantly reduces fibrosis in the bladders of male mice that have been partially obstructed. Here, we investigated if the expression of androgen response genes were altered in mouse bladders after partial bladder outlet obstruction (PO). Using a QPCR microarray and QRTPCR we found that PO was sufficient to increase expression of the androgen response gene Nkx3.1. Consistent with this was an increase in the expression of NKX3.1 protein. Immunofluorescent antibody localization demonstrated nuclear NKX3.1 in most bladder cells after PO. We tested if genetic deletion of Nkx3.1 alters remodeling of the bladder wall after PO. After PO, Nkx3.1 ^KO/KO bladders underwent remodeling, demonstrating smaller bladder area, thickness, and bladder: body weight ratios than obstructed, wild type controls. Remarkably, Nkx3.1 ^KO/KO specifically affected histological parameters of fibrosis, including reduced collagen to muscle ratio. Loss of Nkx3.1 altered collagen and smooth muscle cytoskeletal gene expression following PO which supported our histologic findings. Together these findings indicated that after PO, Nkx3.1 expression is induced in the bladder and that it mediates important pathways that lead to tissue fibrosis. As Nkx3.1 is an androgen response gene, our data suggest a possible mechanism by which fibrosis is mediated in male mice and opens the possibility of a molecular pathway mediated by NKX3.1 that could explain sexual dimorphism in bladder fibrosis.