Microarray Analysis After Preoperative Dietary Restriction Reveals Potential Mechanisms Involved in the Protection Against Ischemia-Reperfusion Injury.

Abstract

Background. Ischemia-reperfusion injury (IRI) is inevitable during kidney transplantation and leads to oxidative stress and inflammation. We previously reported that short-term preoperative dietary restriction (DR), 3-day fasting and protein-free diets protect against renal IRI while a fat-free or carbohydrate-free (CHO-free) diet do not. To understand underlying mechanisms, we performed microarrays and compared gene expression profiles of (non)-protective diets in search for pathways involved in the effect. Methods. Male C57BL/6 mice were randomized to preoperative normal food or: 2 weeks 30%DR, 3-day fasting, 3-day protein-free, 3-day CHO-free or 3-day fat-free diet. Kidneys were harvested after each diet. Gene expressions were analysed by Affymetrix array and pathway analysis was done with Ingenuity. Cut-off for significance was set on fold change ≥1.5 and p-value <0.05. Results. Compared to ad libitum fed, 2 weeks 30%DR resulted in 492 differentially expressed genes (DEG). Similarly, 3-day fasting led to 2604 DEG and a protein-free diet to 391 DEG. The fat-free diet resulted in zero DEG and a CHO-free diet in 1717 DEG. Seventy DEG overlapped in all 3 protective diets, with an overlap of 30 with CHO-free. Ingenuity analysis revealed the involvement of metabolic processes like retinol biosynthesis as well as stress responses like Nrf2-pathway. Preliminary in depth analysis shows differences in these pathways between the protective diets and CHO-free, in which genes like txnip and mrp1 may play a central role. Conclusions. This unique microarray dataset of different dietary interventions points to the involvement of pathways related to oxidative stress resistance and retinol metabolism in the beneficial effects against renal IRI. Since the non-protective CHO-free diet also induced activation of these pathways, further exploration is needed. Collectively, these data suggest that a combined action of both metabolic and stress resistance pathways results in protection against IRI given by preoperative dietary interventions.