Gene expression profile during acute rejection in rat-to-mouse concordant cardiac xenograft by means of DNA microarray

Using a rat-to-mouse concordant cardiac transplantation model and DNA microarrays, we studied the gene expression profiles during acute rejection. We used inbred BALB/c and C3H/He mice and Lewis rats for our study, in which heterotopic cardiac transplantations were performed. Total RNA was isolated from xenografts (Lewis to C3H), allografts (BALB/c to C3H), rat isografts (Lewis to Lewis) and mouse isografts (C3H to C3H) on day 5 following transplantation. We screened for gene expression profiles in the xenografts, allografts, and mouse isografts by means of DNA microarrays. With a murine array, we determined that many IFN-gamma inducible genes were profoundly expressed in both the allografts and xenografts relative to the isografts. Mac-1 was specifically induced in the xenografts relative to the allografts. Using a rat array, we observed that the cardionatrin and atrial natriuretic factors were most profoundly expressed in the xenografts in comparison with the rat isografts. In addition to known genes, many expressed sequence tags were induced in the xenografts. We identified a group of genes, including Mac-1 induced specifically in xenografts, as well as many new genes upregulated in xenografts.