A belső rectushüvelyből képzett artériás érgraftok izometriás tenziójának mérése

Abstract

A Semmelweisz Egyetem, a Gröningeni Egyetem és a Szent István Egyetem Állatorvos-tudományi Kar közös kísérletsorozatának, tudományos együttműködésének eredményeként a rectus hüvelyből képzett autológ érgraft kifejlesztését és felhasználását tovább vizsgáltuk és izometriás méréseket folytattunk. A kísérletet 4, különböző ivarú, beagle fajtájú kutyán végeztük. A kísérlet célja: a graftok 3 hónapos megfigyelése után, azokat eltávolítottuk és izometriás teszteknek vetettük alá. A graftokat úgy alakítottuk ki, hogy magába foglalja a rectus abdominist borító izompólyát és a peritoneum fali lemezét is. Az interpositumot vég a véghez technikával, az arteria iliaca extrena-ba ültettük be. Az artériába beültetett rectus hüvelyt fizikális és doppler-ultrahangos vizsgálatokkal ellenőriztük a reoperáció idejéig. A kutyákon heparinos véralvadásgátlást alkalmaztunk, amelyet posztoperatív gyulladásgátlással egészítettünk ki. Immunszupresszánsok adására nem volt szükség, mivel a holograftok esetében ilyen fajta terápiának nincs indikációja. Az leggyakrabban előforduló perioperatív szövődmény a stenosis és a thrombosis volt. A Semmelweis Egyetemen végzett izometriás tesztek során a kipreparált érszakaszokat további élettani vizsgálatoknak vetettük alá. Az eredményeket figyelembe véve elmondható, hogy a graftok a transzmitterek hatására ugyan úgy reagáltak ( kontrakció vagy relaxáció) mint a kontroll erek, csupán annak intenzitásában volt eltérés.

The present experimantal study is the third phase of project aiming to testly the rectus sheath graft as autologous vascular substitute. Autologous vascular grafts developed from the internal rectus sheath were implanted on both sided arteria iliac externa of experimental beagle dogs. The cavity of the the premedicated, intubated and anaesthetized dogs were exposed using lower median laparatomy. A 2cmx 1,5 cm piece of the right rectus sheath was tubularized with polypropylen sutur using a glass rod. After the arteria iliaca externa was cleaned of peritoneum, clamped with forceps and cut 3 cm away from the fork of iliaca.The grafts were implanted between two cut ends of the bilateral artery. During the posoperative period the general state, the circulation of the hindlimb and the femoral pulse were examined physically.The dogs received heparine as anticoagulant and were treated by antiinflammatory medicine postoperatively. Immunesuppresants were not required as holografts dont indicate such treatment. During the development and the implanting of the grafts no technical difficulties or perioperative complications were encountered. In the postoperative period the morphologic and functional characteristics of the implanted grafts were examined by Doppler ultrasonography. None of these check-ups showed obturation or stenosis. 3 months after the procedures was the reoperation The implanted sections were removed and placed in cold, owygenated Krebs solution. All arteries werw cut transversely into precies ring lenngths by fixed doubledladed scalpel. The arteries were stored at room temperature in gassed Krebs solution and immediatly suspended on wire hooks. One hook was suspended from a transducer. The vessels were allowed a 30-minute equilibration period during which the bath solution was warmed to 37°C and the resting tension was adjusted to 40 mN. Thereafter, the segments were exposed to 124 mmol/L K+ Krebs solution made by isosmolar replacement of Na+ by K+ to elicit reference contraction. Thirty minutes later the vessels were subjected to increasing concentrations of phenylephrine (0.01 to 10 µM). To investigate the functional integrity of the endothelium, acethylcholine (ACh) was tested after a stable plateau of contraction had been reached. Thirty minutes after washing out the ACh, the vessels were exposed to the thromboxane A2 mimetic U46619. The isometric tension recording of the artery segments was made with the MP100 System, and the recorded data were analyzed with the AcqKnowledge 3.8.2 software (BIOPAC System Inc, Goleta, CA). In case of ACh the response was recorded as the cumulative relaxation response at each dose. The transmitters induced a stable contraction or relaxation in the control vessels. However, the solutions also contracted/relaxed the grafts, but the contraction was smaller. As conclusion the study has indicated that the evaluated technique has potential to zse as vascular substitution in the human as well as veterinary clinical field.