Ultrasound: A Valuable Translational Tool to Measure Postvoid Residual in Awake Rats?

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.

50 week ultrasound imaging and ultrastructural abnormalities of bladder after sugar diuresis and diabetes mellitus in rats

PURPOSE

To investigate 50 week ultrasound imaging and ultrastructure changes of bladder in diuresis and diabetes rats.

METHODS

Forty-two healthy male Sprague-Dawley rats were randomly divided into control group, sugar-induced diuresis group and streptozotocin-induced diabetes group. The 24 h drinking and urine volume were calculated from 21 to 31 weeks. Using ultrasound to assess bladders after 49 weeks. Bladders were examined by transmission electron microscope after 50 weeks.

RESULTS

The drinking and urine volume significantly increased in the diuresis and diabetes groups. The bladder morphology and bladder wall thickness increased in the diuresis and diabetes groups. Bladder stones, bladder overdistension and urinary retention were seen in the diuresis and diabetes groups. Urothelium manifested degeneration, denudation and necrosis in the diuresis and diabetes groups. The mitochondrial vacuolar degeneration in the urothelial cells was seen in the diabetes group. The subepithelial vascular endothelial cells hyperplasia with a narrowed lumen were observed in the diabetes group. Abnormal mitochondria were rarely seen in the control group. The mitochondrial vacuolar degeneration in the detrusor was more severe in the diabetes group than in the diuresis group. The detrusor muscle and axon degeneration were observed in the diuresis and diabetes groups. Two rats in the diuresis group share similarities with diabetes group (2/6).

CONCLUSION

Long-term diabetes mellitus can cause increments of urinary bladder morphology and bladder wall thickness, urinary retention and bladder stones. Ultrastructural degeneration of the bladder might be the morphological bases of diabetic cystopathy.