Establishment And Application Of Rat Peritoneal Dialysis Model

Object:To solve the problem of drainage difficulty in the existing rat peritoneal dialysis(PD)models and to establish a rat peritoneal dialysis treatment model conforming to the clinical peritoneal dialysis process.Explore the appropriate peritoneal dialysis treatment program for chronic renal failure(CRF)rat and verify the efficiency of dialysis.To observe the effects of high,medium and low dietary salt load on the biochemical parameters and renal pathology of rats with chronic renal failureand on peritoneal dialysis treatment,and to explore the possible relationship between dietary salt intake and renal injury in rats.Methods:1.Establishment of rat PD modelSPF grade Sprague-Dawley(SD)rat.CRF model is established by 5/6 nephrectomy.4 weeks after 5/6 nephrectomy,peritoneal dialysis tube implantation is performed.Simple steps of peritoneal dialysis tube implantation:using innovative sleeve type dialysis device,the external tube was fixed under the skin of rats,with one end entered the abdominal cavity and the other end from the skin outlet;the internal tube was inserted into the abdominal cavity of rats through the external tube;fixation and sealing.Path of catheterization:the catheter enters the abdominal cavity from the right lateral abdominal wall of the rat,and sliding down perpendicular to the long axis of the body in the abdomen to the midline of the abdomen.Peritoneal dialysis treatment is started one week after the implantation of peritoneal dialysis tube.2.PD treatment regimenThe peritoneal dialysis solution with a glucose concentration of 2.27%,the perfusion amount is 100 ml/Kg,the dwelling time is 4 hours,and the dialysis is performed twice a day for a total of 2 weeks.The amount of perfusion and the amount of drainage per dialysis are recorded and the amount of ultrafiltration is calculated.The changes of serum creatinine and blood urea nitrogen levels in the CRF rats treated with dialysis for 2 weeks are observed to evaluate whether the peritoneal dialysis r has therapeutic effects.On the basis of this peritoneal dialysis regimen,the peritoneal dialysis solute clearance is observed in rats:after 2 weeks of dialysis treatment,2.27%peritoneal dialysis solution is perfused with body weight 100 ml/Kg for a total 7 hours dewlling.The peritoneal dialysis fliud is drained 1ml-2ml every 0.5h or 1h,and the creatinine concentration of the drainage fluid is detected.Finally,the time curve of creatinine concentration is plotted with time(h)as the abscissa and creatinine concentration(μmol/L)as the ordinate.3.Kill the rats at the end of the study,collect and accurately measure the amount of peritoneal dialysate.4.The influence of salt loading to CRF&PD rats’ residual renalHealthy rats undergo 5/6 nephrectomy and placed in a peritoneal tube(the same procedure as above),and are randomly divided into three groups,respectively,with high salt(4%NaCl),medium salt(0.4%NaCl)and low salt(0.02%NaCl)feed.PD treatment is started at the same time.The dialysis regimen is the same as above.The changes of systolic blood pressure(SBP),serum sodium,serum creatinine(Scr)and blood urea nitrogen(BUN)are compared between the three groups through 2 weeks PD treatment.At the end of the study,rats’ kidney tissues are taken for HE and Masson staining,and the pathological changes of the kidney are observed.The tubulointerstitial fibrosis score is performed and compared between the three groups.Result:1.Establishment of rat PD modelThirty rats were selected for the establishment of PD model.Twenty-four rats underwent peritoneal dialysis treatment(3 accidental deaths during dialysis and 3 withdrawals due to peritonitis).The ultrafiltration was 1.11 ml±6.91 ml.2.Adequacy of drainageThere was no significant difference between the intraperitoneal fluid volume(37.00 ml±10.64 ml)at the end of the study and the drainage volume(38.30 ml±7.60 ml)among those rats(t=0.44,P=0.668).3.CRF PD rat creatinine clearancePeritoneal creatinine clearance was detected in 9 normal saline-loaded CRF rats,and the phase diagram of drainage fluid creatinine concentration was plotted.The results showed that glucose 2.27%peritoneal dialysis solution(100ml/Kg),when the dialysate stayed for 4h,the creatinine level of the drainage fluid no longer increased-reaching the plateau stage,at which time the creatinine exchange between the blood and the peritoneal fluid reached equilibrium.4.Efficacy of peritoneal dialysisAfter the PD treatment,the serum creatinine level and urea nitrogen level of 24 CRF rats decreased by 7.29 μmol/L±14.57μmol/L and 4.48 mmol/L±7.75 mmol/L respectively(P=0.022,P=0.009).5.Effect of salt loading on CRF PD rats’ residual kidneyThere were no significant differences in serum sodium,SBP,Scr and BUN between the three groups on the before dialysis time point.After two weeks of PD treatment,the SBP and serum sodium levels were increased in the high-salt group(P=0.000,P=0.003).The SBP level of the low salt group decreased(P=0.000).At the end of the study,SBP(195.37±5.52 mmHg),serum sodium(179.5±17.94 mmol/L),serum creatinine(89.00±8.16μmol/L)and renal tubulointerstitial fibrosis scores[3.00(3.00,3.75)]in the high-salt group were higher than the corresponding values of the middle and low salt rats(P=0.000,P=0.018,P=0.023,P=0.025).Conclusion:1.Establishment of PD treatment model in rats:the problem of blockage has been solved by innovative sleeve-type dialysate device,which ensuring smooth and sufficient drainage.Serum creatinine and urea nitrogen in CRF rats decreased after dialysis treatment,reflecting the role of peritoneal dialysis in eliminating uremic toxins.2.The PD regimen suitable for CRF rats:glucose concentration 2.27%peritoneal dialysis,perfusion by weight 100ml/Kg,dwelling 4h/time,dialysis 2 times/day.According to this description,the curative effect can be seen in two weeks.3.High salt intake aggravates the residual kidney damage in CRF peritoneal dialysis rats,but no significant difference is found between medium and low salt load.