BACKGROUND:The selective immunosuppression on transplanted organ was realized by local drug delivery system,which is one of efficient ways to avoid many kinds of side reactions induced by systemic drug delivery.By using the characteristics that adrenal gland can secret glucocorticoid,the adrenal gland or adrenal implant as the way of local drug delivery of glucocorticoid for transplanted organ is hopeful to avoid the complications induced by systemic and amount of use of glucocoticoid.OBJECTIVE:To establish a model of adrenal gland self-implantation in greater omentum,and to observe the protection of the adrenal gland implant on transplanted liver.DESIGN,TIME AND SETTING:This randomized controlled animal experiment was performed in the Experimental Animal Center of Guizhou Provincial People's Hospital from May 2007 to October 2008.MATERIALS:Fifty male Sprague Dawley rats were assigned as donors,and fifty male inbred strain Wistar rats were assigned as recipients.METHODS:After feeding one week,the recipient rats were randomly divided into two groups with 25 rats in each group.In liver transplantation after adrenal gland self-implantation in greater omentum group,allogenic liver transplantation was performed after successful model establishment of adrenal gland self-implantation in greater omentum.In simple liver transplantation group,only allogenic liver transplantation was performed.No immunosuppressant was used after transplantation in both of the two groups.MAIN OUTCOME MEASURES:The survival time of rats was observed.The morphology of the transplanted livers and the adrenal implants was observed at different time points.The activities of serum aspartate aminotransferase(AST),as well as the concentration of serum corticosteroid and total bilirubin were detected at different time points.RESULTS:The recipient adrenal implants recovered their endocrinal function at 7 weeks after adrenal gland self-implantation in greater omentum.After liver transplantation,histological examination showed that the adrenal implants survived well.The median survival time of rats in the liver transplantation after adrenal gland self-implantation in greater omentum group was more than 30 days,which is obviously longer than that(12 days) in the simple liver transplantation group.There was no significant difference in concentration of serum corticosteroid between the two groups.At 7 days after transplantation,activities of serum AST and concentration of total bilirubin of rats in the simple liver transplantation group were significantly higher than those in the liver transplantation after adrenal gland self-implantation in greater omentum group(P ≤ 0.05).In the liver transplantation after adrenal gland self-implantation in greater omentum group,pathological changes of transplanted livers showed as grade 0 according to Williams standard.In the simple liver transplantation group,a mild rejection appeared at 3 days after transplantation,and the pathological changes turned to severe and reached grade 3 according to Williams standard at 7 days.CONCLUSION:Adrenal implant which survives and recovers its endocrinal function after self-implantation in greater omentum has protection on the transplanted liver in early stage.