Experimental study on evaluating testicular ischemia/reperfusion injury with novel lipid microbubbles with matrix metalloproteinase-9 targetin in rabbit

Abstract

Objective To investigate the change of MMP-9 on moderate ischemia / reperfusion injury in rabbit testicles, and to explor the the feasibility of evaluating complete ischemical reperfusion injury(IRI) of the testis by contrast-enhanced ultrasonography with microbubbles(MB) targeted to TMB9 in rabbits. Methods MB and TMB9 were prepared. Twenty-four white rabbits were randomly divided into control group (group SH-1 and group SH-2, threaded but not ligated), ischemia / reperfusion group(group IRI-1 and group IRI-2, selected one side randomly to have testicular complete torsion surgery 4 h after ligation, released to reperfusion 2 h respectively), every group include 6 rabbits. The operated testes of group SH-1 and gruoup IRI-1 were resected after operating for immunohistochemical staining and the mean optical density of MMP-9. Contrast-enhanced ultrasonography of the bilateral testes were performed with MB or TMB9 in group SH-2 and group IRI-2 before IRI, and after IRI. All images were stored in the machine and using professional CEU software to analyse the contrast images. The contrast curve of rabbits′ testis were evaluated [include slope, time to peak(TP), peak intersity(PI), half time(DT/2), the mean transit time(MTT) and area under time-intensity curve]. Then the operated testes of group IRI-2 were resected after operating for the mean optical density of MMP-9. Results Preoperative, the ultrasonic imaging manifestations and the imaging parameters with MB and TMB9 did not see obvious difference between group SH-2 and group IRI-2. After IRI, the testicle of group IRI-2 with TMB9 showed TP forward, PI rise and DT/2 delay compared with group IRI-2 with MB. Immunohistochemistry showed a significantly increase in the expression of MMP-9 in the vascular basement membrane and interstitial of the IRI testes, but did not in those of the control. The mean optical density of MMP-9 of the testicle in group IRI-2 showed lower than that in group IRI-1 after IRI. Conclusions In a testicular IRI model, MMP-9 can be found in vascular basement membrane and interstitial. Contrast-enhanced ultrasonography with TMB9 can be used to evaluate tesicular ischemia-reperfusion injury. Key words: Testis; Reperfusion injury; Microbubbles; Matrix metalloproteinase 9