Diazoxide ameliorates microcirculatory disturbances through PKC-dependent Pathway in I/R-injured rat cremaster muscles

Genome-wide gene expression profiling of ischemia-reperfusion injury in rat kidney, intestine and skeletal muscle implicate a common involvement of MAPK signaling pathway

The mechanisms of ischemia‑reperfusion (I/R) injury have not been fully elucidated to date. In order to determine the genetic involvement across different organs during I/R injury, a DNA microarray approach was used to analyze the gene expression profiles of the kidney, intestine, and skeletal muscle in a rat model of I/R injury. Fifteen male Lewis rats were divided randomly into three different organ groups; a sham operation (control group), 60‑min‑ischemia (Is group) only, and 60‑min‑ischemia plus 60‑min‑reperfusion (I/R group), respectively. The target genes were identified by DNA microarray and studied by quantitative polymerase chain reaction (qPCR). By comparing the I/R group with the control group, a 2‑fold upregulation of 467, 172, and 3932 and a 2‑fold downregulation of 437, 416, and 4203 genes were identified in the kidney, small intestine, and skeletal muscle, respectively. Several commonly upregulated genes associated with mitogen‑activated protein kinase (MAPK) pathways, including Jun, Atf3, junB, Fos, Adm and Dusp 1, were differentially expressed in the I/R group. The mRNA expression levels of the target genes were confirmed by qPCR. The present study hypothesized that the MAPK pathway may function in a common pathway of I/R injury and regulate the pathogenesis through activator protein 1. The findings of the present study contributed to the understanding of the molecular pathways associated with I/R injury.

AICAR preconditioning prevents postischemic leukocyte rolling and adhesion: role of K(ATP) channels and heme oxygenase

OBJECTIVE

We previously demonstrated that pharmacologic activation of AMP-activated protein kinase (AMPK) with 5-aminoimidazole-4-carboxamide 1-beta-D-ribofuranoside (AICAR) 24 hours prior to (AICAR preconditioning; AICAR-PC) ischemia/reperfusion (I/R) prevents postischemic leukocyte-endothelial cell adhesive interactions (LEI) by a mechanism initiated by endothelial nitric oxide synthase (eNOS)-dependent NO production during the period of AICAR-PC. The major aim of this study was to examine the role of ATP-sensitive potassium (K(ATP)) channels and heme oxygenase as mediators of the antiadhesive effects of AICAR-PC during I/R 24 hours later.

METHODS

Intravital fluorescence microscopy was used to quantify LEI in the small intestine of AICAR-preconditioned C57BL/6J mice treated with K(ATP) channel or heme oxygenase inhibitors during I/R 24 hours after AICAR-PC in separate experiments.

RESULTS

I/R induced marked increases in LEI relative to sham control mice, proadhesive responses that were prevented by AICAR-PC 24 hours prior to I/R. The effects of AICAR-PC to prevent postischemic LEI were abolished by K(ATP) channel or heme oxygenase inhibition during I/R.

DISCUSSION/CONCLUSION

Our results indicate that the antiadhesive effects of AICAR-PC are mediated by K(ATP) channel- and heme oxygenase-dependent mechanisms during I/R.

Resveratrol Attenuates Ischemia - Reperfusion-Induced Leukocyte - Endothelial Cell Adhesive Interactions and Prolongs Allograft Survival Across the MHC Barrier

BACKGROUND

Ischemic - reperfusion (IR) injury is a multifactorial process that leads to tissue damage and rejection in composite tissue allotransplantation (CTA). Antioxidant or free radical scavenger may reduce IR injury, so the effects of resveratrol, a natural antioxidant, on amelioration of leukocyte - endothelial cell adhesive interaction and prevention of transplant rejection in CTA were investigated.

METHODS AND RESULTS

In a microcirculatory study, resveratrol significantly reduced the number of IR-induced leukocytes rolling, adhering, and transmigrating in the postcapillary venules of the cremaster muscle. In the CTA study using groin skin flap allotransplantation across the MHC barrier 8-11-week-old Brown Norway donors (RT1(n)) and 10-11-week-old Lewis recipients (RT1(l)) rats were randomized into 4 groups: isograft control, allograft control, and 2 groups that received different doses of resveratrol (0.1 or 0.5 mg/kg) for 7 days. Allograft control animals rejected their allograft between 5 and 7 days postoperatively, whereas resveratrol-treated recipients had a moderate survival prolongation compared with the allograft control group. Consistent with these observations, histology results also showed reduction of lymphocytic infiltration and necrosis in resveratrol-treated subjects.

CONCLUSION

Resveratrol treatment prolonged groin skin flap allotransplant survival in the recipient and ameliorated the leukocyte - endothelial cell adhesive interactions that may lead to attenuated and delayed rejection in CTA.