Animal Experimental Study Of Newbiodegradable Magnesium Zinc Alloy Used For Sealing Arteriovenous Fistula

OBJECTIVEThe objective of this study is to evaluate the feasibility 、 safety and biocompatibility of the new biodegradable Mg-6%Zn alloy which is applied for sealing of external iliac arteriovenous fistula in dogs.METHODSAfter new biodegradable Mg-6%Zn alloy was implanted,the activity,diet,incision response and the sealing effect of external iliac arteriovenous fistula of dogs were observed.Pre-and post-operationally,the blood biochemical test,serum zinc and magnesium were performed.After 12 weeks,all beagles were executed by lethal dose of pentobarbital after removal of the liver、heart、lung、kidney and roughly 5 cm of external iliac arteriovenous fistula adopting by hematoxylin and eosin(H&E)staining.At the same time,the external iliac arteriovenous fistula specimens of the experimental animals were taken for Western blot tests and the staining of Masson and elastic fibers.RESULTS1.Technical success rate of external iliac arteriovenous fistula model of beagles was 83.3%;2.Thrombosis was found at implanting position of new degradable Mg-6%Zn alloy in the experimental animals,showing that the sealing effect of external iliac arteriovenous fistula is well;3.The activity and diet of experimental animals between two groups were normal,incision was not obvious signs of infection;4.Pre-and post-operationally,biochemical indicators such as TBiL 、 serum magnesium 、Scr and serum zinc levels 、ALT and BUN were found no statistically significant difference in experimental group compared to control group at each time point;5.H&E assessment,all external iliac arteriovenous fistula specimens of beagles manifested no significant inflammatory response without obvious inflammatory cell infiltration.The all external iliac arteriovenous fistula specimens of experimental group manifested slightly thickened intima than the control group.The interstitium and tubules of kidney did not present abnormal morphology,without inflammatory reaction swelling.The function and structure of alveoli was complete and no PE was observed.Hepatocytes did not show obvious edema or necrosis.Apoptosis or necrosis of myocardial cell was not detected,neither inflammatory cell infiltration nor collagen proliferation was detected;6.Western blot results suggested that the expression levels of Bax、Bcl-2、Caspase-3、TNF-α and NF-κB in experimental group were not higher than the control group;7.The results of elastic fiber and Masson’s trichrom staining of external iliac arteriovenous fistula suggested that the elastic and collagenous fibers in the experimental group were densely and orderly arranged with integrated structure and distinct gradations of the elastic lamina;while the morphology and arrangement of the elastic and collagenous fibers in the control group were disordered with slightly elastic lamina fracture.CONCLUSIONSNew biodegradable Mg-6%Zn alloy used as vascular implant material in the experimental group shows favorable sealing effect of external iliac arteriovenous fistula and does not harm the function of important organs and blood biochemical indicators.It may be a perfect candidate of safe and biodegradable material of vascular materials for sealing external iliac arteriovenous fistula.