Pathologically Research On Congenital Hydronephrosis Ureteropelvic Junction Obstruction

OBJECTIVE:Comparing the distribution of collagen fibers, nerve fibers and interstitial cells of Cajal in the ureteropelvic junction (UPJ) between congenital hydronephrosis patients and control children, discussed the pathogenesis and the clinical significance of congenital ureteropelvic junction obstruction (UPJO) in the etiology of congenital hydronephrosis.MATERIALS AND METHODS:1. Between 2008.4-2009.5, 30 specimen of ureteropelvic junction stenosis tissue were collected. All patients were clinically diagnosed as UPJO, confirmed by surgery and pathological diagnosis. Patients aged from 7 months to 11 years old, with an average 4.7-year-old, 18 males and 12 females. At the same time, 11 children of renal tumors (found no tumor cells infiltrate in UPJ) selected as controls, whose aged from 9 months to 8 years old, with an average 3.2-year-old, 7 males and 4 females. All samples were fixed and paraffin-embedded.2. HE and Masson staining were carried out to investigate the changes of anatomy and collagen fibers. By using immunohistochemical SP method, neurofilament protein and C-Kit expression were detected.3. Observed the distribution and counted the nerve fibers and the interstitial cells of Cajal. Used the SPSS 11.5 Statistical Package to compared the difference between two groups.RESULTS:1. The muscle arrange as inner longitudinal and outer horizontal, and no significant fibrous proliferation in the control group. In UPJ stenosis tissue, fibrous hyperplasia and muscular hypertrophy were found by HE and Masson staining, among which existing obvious thicker collagen hyperplasia, and the diameter of lumen is markly shorter than that of control.2. Nerve fibers exist widespread in control group, in which a stronger expression of microfilaments protein in the smooth muscle layer, nerve fibers were arranged horizontally or vertically. However, microfilaments proteins were negative in most specimens of the lesion segment, only a few samples showed weak positive expression with abnormal morphology. Compared with the control group, the difference was significant (P <0.01).3. In control group, there exsit a large number of C-kit-positive interstitial cells of Cajal. Cajal cells showing spindle-shaped or star-shaped, with two or more than 2 slender processes, brown particles in cytoplasm, large nucleus and small perinuclear cytoplasm. Application of toluidine blue staining, it did not showed as metachromatic. Only a few interstitial cells of Cajal were C-kit expression in muscular lesion segment of UPJ. Compared with the control group, the difference was significant (P <0.01).CONCLUSIONS:1. Collagen fibers, nerve fibers and abnormal distribution of interstitial cells of Cajal are all pathological changes in congenital UPJO.2. Neural elements (decreased nerve fibers and interstitial cells of Cajal) may play an important role in the etiology and pathogenesis of congenital UPJO. 3. Clinically, in order to reduce recurrence, ureteropelvic junction stenosis should be totally removed.