N-acetylcysteine prevents bladder tissue fibrosis in a lipopolysaccharide-induced cystitis rat model

Abstract

Therapeutic options for non-Hunner type interstitial cystitis (IC), which is histologically characterized by fibrosis and mast cell infiltration, are limited. We developed a rat model that replicates chronic inflammation and fibrosis and evaluated the therapeutic effect of N-acetylcysteine (NAC), a well-known anti-fibrotic agent, on the model. Intravesical instillation of lipopolysaccharide (LPS, 750 μg) after protamine sulfate (10 mg) was conducted twice per week for five consecutive weeks. One week after final instillation, 200 mg/kg NAC (n = 10, IC + NAC group) or phosphate-buffered saline (n = 10, IC group) was daily injected intraperitoneally once daily for 5 days. LPS instillation induced bladder fibrosis, mast cell infiltration, and apoptotic tissue damage. Functionally, LPS insult led to irregular micturition, decreased inter-contraction intervals, and decreased micturition volume. NAC significantly improved most of the voiding parameters and reversed histological damages including fibrosis. NAC inhibited the induction and nuclear localization of phospho-Smad2 protein in bladder tissues and the upregulation of genes related to fibrosis, such as Tgfb2 , Tgfb3 , Smad2 , Smad3 , Cxcl10 , and Card10 . This is the first study to demonstrate the beneficial effects on NAC in restoring voiding function, relieving tissue fibrosis and related bladder injuries, in the LPS-induced cystitis rat model.

Synergistic Effects of N-Acetylcysteine and Mesenchymal Stem Cell in a Lipopolysaccharide-Induced Interstitial Cystitis Rat Model

“…Similarly, NAC is also a well-known antioxidant that directly scavenges oxygen-free radicals and inhibits fibrosis. In our previous study, NAC treatment blocked the activation of the TGF-β pathway in which genes such as Cxcl10 (pro-inflammatory) and Card 10 (apoptosis-related) were down-regulated [15].…”

“…Bladder function was evaluated two weeks after the final instillation of LPS/PS under unrestrained and awake state in metabolic cages, as previously described [5][6][7]15].…”

“…To address this issue, we first examined whether a single local administration of M-MSCs with a reduced cell number (50 × 10 3 ; 50K) into the bladder could be effective for ameliorating the bladder voiding function in the chronic IC/BPS animal model in which instillation of PS and LPS into the bladders of rats at once per week for five weeks induces longer lasting and chronic urothelial injury [6,17]. We also examined the therapeutic effect of a daily intraperitoneal injection of NAC, which was beneficial to LPS-induced cystitis or to KC in our previous preclinical studies [8,15] due to its antifibrotic activity.…”

“…Reducing the target dosage of stem cells via the synergistic effects of combination therapy could also be an alternative option. We recently reported the therapeutic effects of N-acetylcysteine (NAC), an anti-fibrotic agent, in the IC/BPS preclinical studies [8,15]. Therefore, this study intended to investigate whether there is a synergistic effect of M-MSCs and NAC in the LPS-induced cystitis model and to seek the possibility of reducing the amount of stem cells used in treating IC/BPS.…”

Current and Future Directions of Stem Cell Therapy for Bladder Dysfunction

“…A limitation of the HCL-IC model is the acute nature of the urothelial damage caused; in humans, IC/BPS is a chronic disease. To generate an IC model with symptoms of a chronic nature, Choo and colleagues used an LPS-IC model to mimic chronic IC/BPS by instillation with protamine sulfate (PS) and lipopolysaccharide (LPS) once weekly for five weeks in 8-week-old female rats [74,75]. Injection of MMSCs also significantly alleviated functional and histological damages in this LPS-IC model [74].…”