Struvite urolithiasis in a B6C3F1 mouse

Abstract

SummaryIn a 2 year carcinogenicity bioassay using B6C3Fl mice, one male mouse developed clinical signs near termination of the study, comprising skin sores around the prepuce, penile prolapse and urine scalding. The predominant finding at necropsy was a markedly distended urinary bladder filled with numerous crystallized particles. Microscopically, there was subacute cystitis with marked hyperplasia of the transitional epithelium. X-ray diffraction analysis of the crystals showed a diffraction pattern characteristic of struvite (ammonium magnesium phosphate). The implications of the spontaneous occurrence of bladder stones in rodents on long-term toxicology studies are discussed.

Proliferative and Nonproliferative Lesions of the Rat and Mouse Urinary System

“…In the rat, calculi are usually composed of calcium phosphate and to a lesser degree magnesium ammonium phosphate (Hard et al 1999; Montgomery and Seely 1990). Similar calculi (struvite) in mice have also been reported (Wojcinski et al 1992). Calculi may arise spontaneously in rodents, and those not associated with xenobiotics are more common in the bladder than in the renal pelvis (Peter, Burek, and Van Zwieten 1986).…”

An additional type of male sterility and inherited urinary obstruction in mice with thet-haplotypeth7

“…Urinary obstruction due to such material did not occur in females or in castrated males. Similar suggestions for the origin of the amorphous material from the accessory glands were made by Bendele & Carlton (1986) and Wojcinski et al (1992). In the case of t h7 the grounds for such a speculation are strengthened by the abnormality in formation of copulation plugs.…”

“…It was present, as was the sterility, in t"/t h2 and t h7 /t h49 males, and not present in males carrying the mutant haplotypes derived from t" 7 , t h7m and t h7m2 . Bendele & Carlton (1986) and Wojcinski et al (1992) recognized two types of urinary obstruction in mice: acute and chronic. In the chronic type the bladder was filled with crystalline material and there were external signs of skin ulceration and inflammation in the preputial area, apparently due to dribbling of urine.…”

Modified Bühner suture technique in a guinea pig (Cavia porcellus) with penile prolapse

“…Additionally, urolithiasis is commonly seen in guinea pigs and other rodents and is a potential cause of penile prolapse (Wojcinski and others 1992, Capello 2011). Penile prolapse is reported most frequently in a similar hystricomorph rodent, the chinchilla.…”

“…Penile prolapse in guinea pigs may occur in adult boars due to attempted urinary catheterisation or after natural stretching of the preputial or perineal sacs causing entrapment of foreign bodies (such as food and bedding particles) within the preputial sac causing a subsequent penile irritation and/or infection (Wagner 1976, Richardson 2000, Quesenberry and others 2011). Additionally, urolithiasis is commonly seen in guinea pigs and other rodents and is a potential cause of penile prolapse (Wojcinski and others 1992, Capello 2011). Penile prolapse is reported most frequently in a similar hystricomorph rodent, the chinchilla.…”