| Objective:This study aims to establish an animal model of semi-permanent CVC which can simulate the functions of CVC used by maintenance hemodialysis patients, observing the effects of catheters and the changes of related vasoactive factors(NO,ET-1) and the vascular tissue placed with catheters. To understand the risk factors and mechanism of the occurrence and development of hemodialysis catheters dysfunction and the associations with the changes of the vascular tissue placed with central venous catheters, thus to provide some reference for the application and protection of the central venous catheters in clinical, and make a foundation to study the mechanism of interventions in hemodialysis catheters dysfunction and related complications further.Methods:Thirty healthy dogs (provided by the Experimental Animal Center of Tianjin Medical University), weight (25±5) kg, male or female. Thirty dogs were randomly divided into two groups:A group (control group), B group (catheter group). Routinely implement ultrasound examination to understand the vascular conditions:using two-dimensional and vascular color Doppler clearly show the femoral vein trunk vessels before femoral vein cannulation. Make surface markers of subcutaneous tunnel and the import and export of catheter preoperative. Placed right femoral vein catheter according to seldinger method with avulsion type dilators. Do X-ray fluoroscopy examination to determine the location of the catheter tip postoperative. Fasting blood samples of all the subjects were obtained on the day of operation, postoperative one week, two weeks, three weeks, four weeks which were used to measure serum endothelin-1and nitric oxide concentrations by Elisa method. The catheter group subjects were carried on blood circulation every other day from the first day after operation. All animals were sacrificed on the fourth week after operation, then removed the semi-permanent catheter, intact section femoral vein from the entrance to the catheter tip and the contralateral femoral vein of equal length. The specimens were stained with HE method after segmented and labeled and then observed by optical microscope. Application of SPSS17.0statistical package for statistical analysis of all data, P<0.05was considered statistically significant.Results:(1):The serum NO and ET-1levels of control group and experimental group animals have no significant difference (P>0.05) on the day of operation; the serum NO and ET-1levels of the first week after operation were higher than the levels on the day of operation (P<0.05); the serum NO and ET-1levels recovered to the day of operation which lasted for the fourth weeks since second weeks after (P>0.05).(2):The proximal and distal vascular intima of catheters tip at the outlet were thicken compared with the control vascular; the proximal vascular intima is more thicken than the distal vascular intimal (P<0.05).Conclusion:(1):Animal models of central venous catheter on dogs were established successfully which could simulate the functions of semi-permanent catheters within hemodialysis patients such as providing adequate blood flow for blood circulation and so on.(2):The changes of hemodynamic after the placement of catheters could lead to changes in the concentration of endothelin-1and nitric oxide and result intimal hyperplasia. |
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