Abdominal fur was removed and a 15 mm low transverse abdominal incision was made lateral to midline. prior animal models of obstruction. These observations suggest that the mgb mouse represents a unique small animal model for the study of CON. Congenital obstructive nephropathy (CON) is usually a complex disease including pathologic changes in kidney development and function that occur as a result of obstructed urine flowin utero. CON is the most common cause of chronic renal failure in children (1). Its clinical course and end result are dependent on the developmental stage at which the obstruction occurs, the degree and duration of the obstruction, and whether one EBI-1051 or both kidneys are involved. Although surgical intervention can relieve some effects of CON, many pathologic changes associated with this condition appear irreversible (2). Diagnostic, therapeutic and prognostic quandaries often arise in the management of CON, creating a significant need for animal models of this important disease. We recently recognized a unique mutant mouse, designatedmgbformegabladder. These mice develop indicators of lower urinary tract obstructionin uterosecondary to a non-functional, over-distended bladder, with indicators of renal failure evident shortly after birth (3). Male homozygotes (mgb/) develop early renal insufficiency and rarely survive beyond 46 weeks, while femalemgb/mice may live up to a 12 EBI-1051 months (3). The aim of this study was to assess and compare the progression of renal disease inmgb/mice with prior experimental and genetic models of obstruction as well as human CON. == METHODS == == Mice == Animals were maintained according to NIH Guideline for the Care and Use of Laboratory Animals, with approval from your Institutional Animal Care and Use Committee of Nationwide Childrens Hospital. Developmental stages included embryonic day 15.5 (E15.5), E17.5, newborn (NB, postnatal day 03), and adult (AD, 3 weeks or older). Controls were age-matched FVB/N mice. Genotyping was performed as previously explained (3). == Histological Analysis == E15.5 embryos and individual kidneys were fixed in 10% formalin. Masson’s trichrome was TSPAN9 performed using Sigma-Aldrich Trichrome kit (St. Louis, MO). Hematoxylin and eosin staining was performed using standard procedures. Qualified veterinary pathologists at Vet Path Services, Inc. (Mason, OH) or The Mouse Phenotyping Core (The Ohio State University or college, Columbus OH) performed histopathological assessments. Tissues were processed in Leica TP 1050 Automatic Tissue Processor (Leica Microsystems, Wetzlar, Germany), and stained with antibodies for -easy muscle mass isoactin (-SMA, DakoCytomation, Carpinteria CA); F4/80 (AbD Serotec, Raleigh NC); aquaporin-2 (AQP2), TGF-1, connective tissue growth factor (CTGF), Wilms tumor 1 (WT-1) (Santa Cruz Biotechnology, Santa Cruz CA), E-cadherin (Cell Signaling, Danvers MA), and paired box EBI-1051 gene 2 (Pax2, Invitrogen, Camarillo CA) as outlined by suppliers. TUNEL was performed according to manufacturers instructions (CalBioChem, Gibbstown NJ). 3-Dimensional reconstruction and quantitation were performed using StereoInvestigator and Neurolucida Explorer (MBF Bioscience, Williston VT). Section intervals were set to desired z-depth and outer limits of each structure traced and enclosed at optimal magnification. Sections were aligned, stacked and connected using 3-D wireframe view, quantitated and compared by t-test. A 50m grid was overlaid on each 10X image and fibrosis graded as less than or greater than 50% positive staining. Total percentage of grid squares with >50% positive staining was calculated EBI-1051 by software. Positively-staining glomerular cells were counted by hand. Results were compared by t-test. == Renal Ultrasound == Renal ultrasound was performed on 2, 4 and 5-week male mice using VisualSonics In Vivo Model RMV-704 and 40MHz small animal probe (Toronto, Ontario). Total renal length (RL) and renal pelvic anterior-posterior diameter (APD) were measured. Hydronephrosis was scored by the ratio of APD to RL. Individual kidneys were classified as no hydronephrosis (APD/RL=0), moderate (APD/RL>1SD below imply), moderate (APD/RL=imply1SD), or severe hydronephrosis (APD/RL>1SD above imply). == Vesicostomy == 4-week aged malemgb/mice underwent vesicostomy using inhalation anesthesia. Abdominal fur was removed and a 15 mm low transverse abdominal incision was made lateral to midline. Peritoneum was divided transversely and bladder brought into the surgical field. A 24-gauge angiocatheter was launched into the bladder and contents aspirated. After catheter removal, cystotomy was enlarged and four-quadrant fixation of bladder edges to peritoneum and abdominal wall was performed with interrupted 6-0 polydiaxone sutures. Additional sutures were added for circumferential closure. Antibiotic ointment was applied and stomal patency monitored. == RESULTS == == Disease Stratification == Renal injury was stratified inmgb/mice using renal ultrasound (Fig. 1). Eighteenmgb/mice and 19 age-matched.