Perconditioning combined with postconditioning on kidney ischemia and reperfusion

Ischemic perconditioning on mesenteric ischemia/reperfusion injury in rats

Purpose:

To evaluate if the perconditioning affects the antioxidant capacity in mesenteric ischemia and reperfusion injury.

Methods:

Twenty-one Wistar rats were assigned into three groups, as follows: Sham, IR and rPER. The animals were subjected to mesenteric ischemia for 30 min. rPER consisted of three cycles of 5-min hindlimb ischemia followed by 5 min hindlimb perfusion at the same time to mesenteric ischemic period. After 5 minutes, blood and 5 cm of terminal ileum were harvested for thiobarbituric acid reactive substances (TBARS) and Trolox equivalent antioxidant capacity (TEAC) measurement.

Results:

rPER technique was able to reduce intestinal tissue TBARS levels (p<0.0001), but no statistic difference was observed in blood levels between groups, although it was verified similar results in rPER and Sham group. rPER technique also enhanced TEAC levels in both blood (p = 0.0314) and intestinal tissue (p = 0.0139), compared to IR group.

Conclusions:

rPER appears as the most promising technique to avoid IR injury. This technique reduced TBARS levels in blood and intestinal tissue and promoted the maintenance of antioxidant defense in mesenteric acute injury.

Remote ischemic conditioning improves rat brain antioxidant defense in a time-dependent mechanism

Purpose

To clarify the best protocol for performing remote ischemic conditioning and to minimize the consequences of ischemia and reperfusion syndrome in brain, the present study aimed to evaluate different time protocols and the relation of the organs and the antioxidant effects of this technique.

Methods

The rat’s left femoral artery was clamped with a microvascular clamp in times that ranged from 1 to 5 minutes, according to the corresponding group. After the cycles of remote ischemic conditioning and a reperfusion of 20 minutes, the brain and the left gastrocnemius were collected. The samples were used to measure glutathione peroxidase, glutathione reductase and catalase levels.

Results

In the gastrocnemius, the 4-minute protocol increased the catalase concentration compared to the 1-minute protocol, but the latter increased both glutathione peroxidase and glutathione reductase compared to the former. On the other hand, the brain demonstrated higher catalase and glutathione peroxidase in 5-minute group, and the 3-minute group reached higher values of glutathione reductase.

Conclusions

Remote ischemic conditioning increases brain antioxidant capacity in a time-dependent way, while muscle presents higher protection on 1-minute cycles and tends to decrease its defence with longer cycles of intermittent occlusions of the femoral artery.

Opioids Preconditioning Upon Renal Function and Ischemia-Reperfusion Injury: A Narrative Review

Kidneys have an important role in regulating water volume, blood pressure, secretion of hormones and acid-base and electrolyte balance. Kidney dysfunction derived from acute injury can, under certain conditions, progress to chronic kidney disease. In the late stages of kidney disease, treatment is limited to replacement therapy: Dialysis and transplantation. After renal transplant, grafts suffer from activation of immune cells and generation of oxidant molecules. Anesthetic preconditioning has emerged as a promising strategy to ameliorate ischemia reperfusion injury. This review compiles some significant aspects of renal physiology and discusses current understanding of the effects of anesthetic preconditioning upon renal function and ischemia reperfusion injury, focusing on opioids and its properties ameliorating renal injury. According to the available evidence, opioid preconditioning appears to reduce inflammation and reactive oxygen species generation after ischemia reperfusion. Therefore, opioid preconditioning represents a promising strategy to reduce renal ischemia reperfusion injury and, its application on current clinical practice could be beneficial in events such as acute renal injury and kidney transplantation.

Hypertonic solution-induced preconditioning reduces inflammation and mortality rate

Background

Dysregulated inflammatory response is common cause of organ damage in critical care patients. Preconditioning/tolerance is a strategy to prevent exacerbated inflammation. The aim of this study is to analyze hypertonic saline 7.5% as a potential inducer of preconditioning that protect from a lethal dose of LPS and modulates systemic inflammatory profile in mice.

Methods

Male Balb/C mice received intravenous (i.v.) injections of Hypertonic solution (NaCl 7.5%) (0.8 ml) for 3 days, on day 8th was challenged with LPS 15 mg/kg. Controls with Saline 0.9%, urea and sorbitol were performed. Microarray of mRNA expression was analyzed from HS versus saline from macrophages to identified the pathways activated by HS.

Results

HS preconditioning reduced mortality after LPS injection as well reduced the cytokines release in plasma of the animals challenged by LPS. In order to check how HS induces a preconditioning state we measured plasma cytokines after each HS infusion. Repeated HS injections induced a state of preconditioning that reprograms the inflammatory response, resulting in reduced inflammatory cytokine production. A microarray of mRNA demonstrated that Hypertonic solution increased the expression of several genes in special Mapkbp1 and Atf3.

Conclusion

hypertonic solution induces preconditioning/tolerance reducing mortality and inflammatory response after LPS challenge.