Establishment of animal model manifested as bladder neurogenic changes generated by bilateral pelvic nerve injury in male rats

Transcriptomics Reveals Molecular Features of the Bilateral Pelvic Nerve Injury Rat Model of Detrusor Underactivity

The pathogenesis of detrusor underactivity (DU) is unclear, and the available therapeutic effects are unsatisfactory. We propose to find key molecules and pathways related to DU based on transcriptome sequencing. A rat model of bilateral pelvic nerve injury (BPNI) was established. Bladder tissues from the sham-operated group, 3 and 28 days after BPNI mapping, were taken for urodynamics, histopathology, and RNA-seq. An enrichment analysis of the screened differential expression genes was performed. Three days after BPNI, the results showed urodynamic features of overflow incontinence, while there was a recovery at 28 days after the operation. Masson staining revealed collagen deposition accompanied by progressive thickening of the smooth muscle layer as DU progressed. RNA-seq results suggested that a total of 1808 differentially expressed genes (DEGs) differed among the groups. RNA-seq and subsequent analysis confirmed that the cell cycle and immune response were significantly activated 3 days after BPNI, while extracellular matrix remodeling occurred 28 days after BPNI. Partial DEGs and pathways were verified by qRT-PCR. Validation of key proteins involved in cell cycle, inflammation, and fibrosis was performed by immunohistochemical staining and western blot, respectively. These molecular expression patterns at different time points after BPNI injury provide valuable insights into the search for therapeutic targets for DU.

Functional, morphological and molecular characteristics in a novel rat model of spinal sacral nerve injury-surgical approach, pathological process and clinical relevance

Spinal sacral nerve injury represents one of the most serious conditions associated with many diseases such as sacral fracture, tethered cord syndrome and sacral canal tumor. Spinal sacral nerve injury could cause bladder denervation and detrusor underactivity. There is limited clinical experience resolving spinal sacral nerve injury associated detrusor underactivity patients, and thus the treatment options are also scarce. In this study, we established a spinal sacral nerve injury animal model for deeper understanding and further researching of this disease. Forty 8 w (week) old Sprague Dawley rats were included and equally divided into sham (n = 20) and crush group (n = 20). Bilateral spinal sacral nerves of rats were crushed in crush group, and sham group received same procedure without nerve crush. Comprehensive evaluations at three time points (1 w, 4 w and 6 w) were performed to comprehend the nature process of this disease. According to urodynamic test, ultrasonography and retrograde urography, we could demonstrate severe bladder dysfunction after spinal sacral nerve injury along the observation period compared with sham group. These functional changes were further reflected by histological examination (hematoxylin-eosin and Masson's trichrome staining) of microstructure of nerves and bladders. Immunostaining of nerve/bladder revealed schwann cell death, axon degeneration and collagen remodeling of bladder. Polymerase Chain Reaction results revealed vigorous nerve inflammation and bladder fibrosis 1 week after injury and inflammation/fibrosis returned to normal at 4 w. The CatWalk gait analysis was performed and there was no obvious difference between two groups. In conclusion, we established a reliable and reproducible model for spinal sacral nerve injury, this model provided an approach to evaluate the treatment strategies and to understand the pathological process of spinal sacral nerve injuries. It allowed us to understand how nerve degeneration and bladder fibrosis changed following spinal sacral nerve injury and how recovery could be facilitated by therapeutic options for further research.

Bone marrow mesenchymal stem cells therapy on bilateral pelvic nerve crush-induced voiding dysfunction in rats

INTRODUCTION AND HYPOTHESIS

Neurogenic voiding dysfunction can be induced after radical pelvic surgery and severely affects patients' quality of life. This study aims to investigate the effects of bone marrow mesenchymal stem cells (BMSCs) on neurogenic voiding dysfunction in male rats and explore the underlying mechanisms.

METHODS

Thirty 4-week-old male Sprague-Dawley rats were randomly divided into three groups: (1) sham-operated (sham, n = 10), (2) intrabladder wall injection of phosphate buffer solution (PBS) after bilateral pelvic nerve crush (BPNC+PBS, n = 10), and (3) intrabladder wall injection of BMSCs after bilateral pelvic nerve crush (BPNC+BMSCs, n = 10). Four weeks postoperatively, functional and morphological examinations were performed.

RESULTS

Compared to the sham group, BPNC rats manifested significant augmentation in the frequency of non-voiding contractions and postvoid residual and bladder capacity, and they had decreases in intravesical pressure and voiding efficiency. However, they were markedly improved after BMSC injection. Masson's trichrome staining showed that the ratio of collagen area in bladder wall tissue significantly increased in the BPNC+PBS group but was reduced following BMSC injection. BPNC increased the protein expression of TGF-β1, Smad2/3, and collagen I/III but decreased the expression of α-SMA. BMSC injection stimulated higher expression levels of α-SMA and lower expression levels of the other target proteins. The expression levels of vesicular acetylcholine transporters were reduced at 4 weeks post-BPNC, whereas injection of BMSCs boosted the expression quantity.

CONCLUSIONS

BMSC therapy suppressed detrusor fibrosis, improved intravesical pressure and voiding efficiency, and partially restored voiding function in male rats after BPNC.

Telmisartan inhibits bladder smooth muscle fibrosis in neurogenic bladder rats

Hypertension is associated with bladder symptoms. The present study investigated whether an angiotensin receptor blocker could improve the symptoms and pathological changes associated with a neurogenic bladder (NB). A Sprague-Dawley rat model of NB was constructed. Rats in the sham and model groups were gavaged with saline, and rats in the treatment group were gavaged with telmisartan. Urodynamic parameters, including maximum cystometric capacity, residual urine volume, bladder wet weight, bladder compliance and detrusor pressure, were detected. Masson and H&E staining were performed to assess bladder fibrosis and histopathological changes. The expression levels of basic fibroblast growth factor (bFGF), TGF-β1, Collagen I, Collagen III, and α-smooth muscle actin (α-SMA) were also measured by reverse transcription-quantitative PCR, western blotting and immunohistochemistry. The model rats exhibited symptoms and pathological changes associated with NB. Treatment with telmisartan reduced maximum cystometric capacity, residual urine volume, bladder compliance and bladder wet weight, and increased detrusor pressure in model rats. The tissue staining results showed that telmisartan exerted an antifibrotic effect. In addition, telmisartan inhibited the expression of bFGF, TGF-β1, Collagen I, Collagen III and α-SMA in model rats. Therefore, the results of the present study indicated that telmisartan may serve as a potential therapeutic agent for NB.