Background
Fasting (FA) or dietary restriction (DR) offer robust protection against renal ischemia- reperfusion injury (IRI) in mice. However, the mechanism remains unclear. The adaptive immune system, which plays an important role during IRI, is affected by dietary restriction. IL- 17 producing RORy+y(delta) T-cells are early effectors in IRI. We investigated the impact of FA and DR on y(delta) T-cells during IRI.

Materials and Methods
Male C57Bl/6 mice were fed ad libitum or underwent 72hrs fasting or 2 weeks 30% DR (n=6/group), but no IRI. Other mice were subjected to the three dietary regimens followed by induction of renal IRI. Kidneys were harvested for immunohistochemistry and rtPCR before (no IRI), and, 6 and 24hrs after IRI.

Results
After DR and FA, IRI was ameliorated, as reflected by reduced renal TNF-x expression compared to AL. Also, significantly reduced CD3+ T cell numbers were seen at 6hrs compared to AL. In FA mice y(delta) T-cells were significantly increased at 0hrs, while they decreased at later time points. In AL, the yGT cells were upregulated at 6hrs. RORy expression levels were found to be higher in FA at 0hrs and DR at 6hrs.

Conclusion
Dietary restriction induces pre-activation of antigen unspecific, first linear responder CD3+ RORy+y(delta) T-cells, important in the protection against renal IRI.