Factors influencing the development of Multicystic Dysplastic Kidney (MCDK) following urinary tract obstruction in the fetal lamb.

Creating obstructive uropathy (OU) during glomerulogenesis in the fetal lamb results in multicystic dysplastic kidney (MCDK) at term. We explored this using immunohistochemical techniques. OU was created in fetal lambs at 60-day gestation, ligating the urethra and urachus. The kidneys of MCDK lambs, 60-day gestation fetal lambs, full-term lamb (145 days), term sham-operated lambs, and adult ewes were evaluated by HE staining, and immunohistochemistry with paired box genes 2 (PAX2) and CD10. Multiple cysts were found in the MCDK model. CD10 was expressed in proximal tubular epithelial cells, glomerular epithelial cells, and medullary stromal cells in the kidneys of 60-day gestation fetal lambs and full-term lambs and adult ewes. PAX2 expression was found in ureteric buds, C- and S-shaped bodies, epithelial cells of collecting ducts, and Bowman's capsule of fetal kidneys at 60-day gestation, but only in the collecting ducts of full-term fetal lambs and adult ewes. Both CD10 and PAX2 were expressed in the cystic epithelial cells of the MCDK model. PAX2 expression in cystic epithelial cells suggests that cyst formation is associated with disturbed down-regulation of PAX2 in the nephrogenic zone epithelial cells during the renal development in the OU model.