| Objective:To study the effect of vanillic acid on the formation of infectious stones in rats,a model of infectious stones was established.To observe the pathological changes of urinary tract in rats after vanillic acid intervention and to explore a new type of urease inhibitor.Methods:⑴.In order to establish the model of infective bladder stone in rats,the bladder was punctured under the guidance of ultrasound,and foreign bodies loaded with Proteus mirabilis were implanted into the rat’s bladder,the bladder stones were analyzed by Fourier transform infrared spectroscopy.⑵.The experimental rats were divided into blank control group,sham operation group,model group,acetohydroxmic acid group and vanillic acid group.They were fed with conventional feeding or conventional feeding added with acetohydroxmic acid or vanillic acid.The rats were sacrificed 21 days later,the bladder stones were weighed,the urine was collected and the p H was assayed.All the rats kidney,ureter and bladder were fixed with formalin for pathological examination.⑶.The kidney,ureter and bladder were fixed,embedded,sectioned and stained with HE.The difference of urinary tract between vanillic acid group and other experimental groups was observed.The expression of Tamm-Horsfall protein of the kidney was investigated by immunohistochemical method.Results:Two rats died on the third day after operation,and the dead rats belonged to the open surgery model group.The causes of death were considered as abdominal infection,acute peritonitis and septic shock.No rats died in the ultrasound puncture model group.Stones were formed in the bladder of non-dead rats in the ultrasound puncture model group and open surgery model group,and the composition of stones was magnesium ammonium phosphate by infrared spectroscopy analysis.The mode success rate of the ultrasound guided puncture group was 100%,and 83% in the open surgery group.There was no stone formation in the blank control group rats,and no stone formation in the sham operation rats.Stones were detected in all the other rats bladder,the chemical components was magnesium phosphate.The average stone weigh in the vanillic acid group was lower than that of acetohydroxamic acid group,and both of them were significantly lower than that of the model group.The urine p H of vanillic acid group and acetohydroxamic acid group was significantly lower than that in model group.No obvious pathological changes were found in the kidney,ureter and bladder of the blank control group and sham operation group rats,and the other three groups had different degrees of inflammatory reaction.Rats in the model group showed severe urinary tract inflammation,followed by those in the acetohydroxamic acid group.In the vanillic acid group,the urinary tract tissue lesions were the mildest,showing a small amount of inflammatory cell infiltration and mucosal hyperplasia in the urinary tract tissue,and no serious pathological changes such as mucosal loss was observed.Compared with the model group and the acetohydroxamic acid group,the expression of Tamm-Horsfall protein in the thick segment of the ascending branch of Henry loop and the proximal segment of the distal convoluted tubule of the rats in the vanillic acid group was not significant.Conclusion:Infectious stone model can be constructed by ultrasound-guided puncture of rat bladder and implantation of polyurethane catheter loaded with Proteus mirabilis.This method has the advantages of rapid stone formation,high stone formation rate,fewer complications in animals and low mortality.Proteus mirabili can cause inflammation damage of urinary tract epithelium and renal parenchyma.Vanillic acid can inverse the inflammatory injuries.Compared with acetohydroxamic acid,Vanillic acid can strongly inhibit the formation of infectious stones,and can be expected to be a new urease inhibitor,using in the treatment or prophylaxis of infectious urolithiasis. |
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