Background: Caspase-3 associated with apoptosis and inflammation plays a key role in ischemia reperfusion injury. The naked caspase-3 siRNA was effective in the cold preservation and ex vivo hemoreperfusion of the kidney, but its in vivo effects need to be further evaluated. Hence, a novel version of naked caspase-3 siRNA with super serum stability was applied in a porcine kidney auto-transplantation model.

Materials and Methods: The left kidney was retrieved from mini pigs and infused by University of Wisconsin solution with/without 0.3 mg caspase-3/negative siRNA (Ambion® In vivo siRNAs, n = 5) into the renal artery with the renal artery and vein clamped for 24-h cold storage (CS). After the right nephrectomy, the left kidney was auto-transplanted into the right for 2 weeks with an i.v. of 0.9 mg siRNA 1-h before reperfusion. The work was performed under the regulation layout by Chinese animal welfare authority.

Results: The expression of caspase-3 mRNA was reduced in both the post-CS and post-transplant kidneys preserved by caspase-3 siRNA, while the caspase-3 precursor was reduced in the post-CS kidneys and 17 kD active subunit was inhibited in the post-transplant kidneys respectively. The level of IL-1Β mRNA, apoptotic cells and myeloperoxidase+ cells, was all decreased in the post-CS and post-transplant kidneys. In addition, HMGB-1 was decreased only in the post-transplant kidneys, but no significant changes were revealed in TLR-3 and TLR-7 between the groups. Moreover, renal tissue damage was ameliorated by the siRNA, with better renal function.

Conclusion: The serum stabilized naked caspase-3 siRNA administered locally and systemically protected transplant kidneys via altering apoptosis, inflammation and immunity responses. Using this novel siRNA in a large animal kidney auto-transplantation model for 2 weeks provides invaluable data for future human clinical trials.

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