| Objectives:1. To establish animal model of partial unilateral ureteral obstruction (PUUO) in rabbit and explore the feasibility on evaluating recanalization effect of PUUO with renal pelvic pressure.2. To investigate whether there is morphological change occurring in renal vascular system of hydronephrosis, and elucidated its underlying relevant morphological mechanisms.Methods:1.24New Zealand rabbits were randomly divided into normal control group (N), PUUO group after4weeks (PUUO4), complete unilateral ureteral obstruction (CUUO) group after4weeks (CUU04) and4weeks group removed after2weeks PUUO (R4),6rabbits each group. The rabbits in PUUO4and CUU04were subjected to left upper ureter obstruction by the method modified of embedding plastic tube into ureter and by ligating ureter with3-0silk suture respectively. The pyelic perfusion pressure of non-perfusion, lml/min,3.5ml/min,5ml/min (perfusion time were10-20seconds) in all groups was measured and morphological change of kidney and ureteral were observed.2. Animal model of CUUO was constructed by ligating left upper ureter with3-0silk suture. New Zealand rabbits were divided into six groups:the normal control group (N), the sham-operated group (sham) and1week (01),2weeks (02),4weeks (04) and8weeks (08) group after CUUO. Blood pressure was measured in all groups, vascular cast of renal artery and its branches were performed with perchlorethylene as vascular fillers, Renovascular diameter was measured by sliding calipers; renovascular cast was completed with bulking agent of perchloroethylene mixed with lead oxide, cast specimens were scanned by64multidetector row computed tomography (CT) and then renovascular three-dimensional reconstruction was performed automatically with CT workstation. The glomerular vasculature was examined by polymethyl methacrylate vascular cast technique; The diameters of afferent and efferent arterioles,glomerular diameters were measured.we also used transmission electron microscope to observe morphological change of glomerular filtration barrier; urine glucose, urine protein and red blood cells of all groups were detected with dry chemical and urine sediment. The renovascular quantitative assessment include measuring the media thickness and the lumen diameter, calculating the media/lumen ratio and the cross-sectional areas of the media.Results:1. The pyelic perfusion pressure of non-perfusion and different perfusion rates in PUU04and CUU04groups were9.17±0.70,14.73±1.13,52.55±3.85,85.47±2.90cmH2O and9.57±0.75,16.08±1.89,53.83±3.62,87.73±3.37cmH2O respectively. No significant difference were found between two groups, the pyelic perfusion pressure of N and R4groups were0.28±0.17,10.07±0.78,15.90±2.49,50.38±3.16cmH2O and7.32±0.77,12.65±1.21,48.45±3.29,67.97±3.51cmH20espectively. In R4group, pyelic perfusion pressure of different perfusion rates were higher than that of N group (P<0.05) and were lower than PUUO4and CUUO4groups (P<0.05) respectively, the ureters obstructed were dilated and renal parenchyma were thin.2. The systolic blood pressures from N to08group were77.0±8.89mmHg,95.10±4.28mmHg,115.00±3.80mmHg,116.30±5.46mmHg,132.30±3.59mmHg respectively, significant difference were found between obstruction and normal control groups (P<0.05). Morphological measurements showed that interlobar artery diameters were decreased in02group, with significant difference were found between the first branch of renal artery, segmental renal, interlobar artery of08and that of N group respectively (P<0.05); Three-dimensional reconstruction clearly demonstrated that the vessels of kidney were rather sparse in08group. Morphological change of glomerular capillary clusters were observed in02group. Compared with the N group, The diameters of afferent and efferent arterioles were markedly reduced below the normal level for groups02to08(P<0.05). Moreover, the glomerular diameter was dramatically decreased as a result of glomerular atrophy. Furthermore, the tortuous even ruptured glomerular basement membrane and fusional foot processes were found in O4and08groups. Urine glucose, urine protein and red blood cells are normal in N group. in obstruction groups, urine protein(+～+++) and microamount urine glucose were discovered, significant difference were found in red blood cell count between N and obstruction groups (P<0.05). In both interlobar artery and afferent arterioles, the media thickness,media/lumen ratio was markedly increased in groups02to08, compared to the N group, the lumen diameter gradually decreased with obstruction time(P<0.05), the cross-sectional areas of the media were unaltered between the N group and the obstructed groups.Conclusions:1. measurement of renal pelvis perfusion pressure can be used as one of methods of detecting recanalization effect in PUUO animal model. The recanalization effect was not ideal, it is necessary to establish an ideal animal model of PUUO.2. Renovascular morphological change involves not only the preglomerular vessels including interlobular artery, but also glomerular capillary in hydronephrosis progression.3. With the development of hydronephrosis,the blood pressure gradually increased, hypertension induces mechanical lesions of the glomerular capillary wall,these effects result in vascular remodeling, which contributes to renovascular structural changes. |
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