[A modified rat model for infection-induced stone formation].

Objective: To employ a newly modified rat model for infection-induced bladder stone formation.

Methods: 24 adult male Sprague Dawley rats were divided into 3 groups, model group (n=12), sham operation group (n=8) and control group (n=4). The surgical procedures were performed aseptically under anesthesia (25% Ultane 1.0 g/kg). The bladder in model group was exposed through a short lower midline abdominal incision, the puncture needle (G18) with guideline was inserted aseptically into bladder, a metal wire, which have been contaminated by the Proteus mirabilis, was put into the puncture canal, then implanted into the bladder lumen through the guideline. In the sham operated group the puncture needle (G18) with guideline was inserted into bladder without metal wire implanted into the bladder. There was no any operation in control group. The rats were sacrificed by excessive anesthesia at 21 days post challenge. The bladder were removed aseptically and inspected for evidence of urolithiasis.

Results: On Day 2 after surgery, two rats died in model group, no rats died in other groups. Twenty-one days after surgery, all of rats in model group developed various-sized bladder stones. There was no stone formation in sham operation group and control group. All stones were verified by infrared spectroscopy and optical crystallography. These stone were struvite stone.

Conclusion: This model has a less trauma, faster recovery and excellent stone formation so that it may be used for the study of infection stone.