Evaluation of the Effects of Atorvastatin and Ischemic Postconditioning Preventing on the Ischemia and Reperfusion Injury: Experimental Study in Rats

Atorvastatin inhibits ischemia‒reperfusion-associated renal tubular cell ferroptosis by blocking the PGE2/EP4 signaling pathway

Renal ischemia‒reperfusion (I/R) injury is the main cause of acute kidney injury, and its pathological features are manifested primarily by renal tubular epithelial cell injury. The underlying mechanism involves ferroptosis of renal tubular epithelial cells. Atorvastatin (ATO) regulates ferroptosis, and this study explored its role in I/R-induced ferroptosis of renal tubular epithelial cells. We constructed a renal I/R rat model with bilateral renal pedicles using noninvasive arterial clips and placed HK-2 cells in hypoxia/reoxygenation (H/R) incubators to construct the cell model. The damage to rat kidney tissues and HK-2 cells was assessed using enzyme-linked immunosorbent assay (ELISA), hematoxylin and eosin (H&E) staining, and flow cytometry, and the presence of associated proteins was identified through western blotting. Administering ATO markedly lessened the acute kidney damage caused by I/R, decreased the levels of blood urea nitrogen (BUN) and creatinine (CRE), and prevented apoptosis in renal tubular epithelial cells. Treatment with ATO additionally suppressed the production of inflammatory cytokines (TNF-α, IL-1β, and IL-6) and markers linked to ferroptosis (Fe2+, ROS, MDA, ACSL4, and COX2), thereby reducing acute kidney damage associated with I/R. The expression of PGE2 in renal I/R injury is related to the degree of renal injury, and it mainly regulates ferroptosis by binding to EP4. ATO effectively inhibited the expression of PGE2 and EP4. Overall, this study revealed that ATO inhibited ferroptosis of renal tubular epithelial cells by blocking the PGE2/EP4 signaling pathway, thereby alleviating I/R-induced kidney injury.

Effect of Selenium on Lung Injury Induced by Limb Ischemic Reperfusion Injury in Sprague-Dawley Rats

Purpose

: Ischemia-reperfusion injury (IRI) plays an important role in the pathophysiology of acute limb ischemia, leading to damage to distant organs, including the lungs. A complex mechanism is involved in the formation of reactive oxygen species (ROS), release of inflammatory mediators, and neutrophil activation. One strategy to reduce the damage is administering selenium, an antioxidant enzyme component that can bind ROS and protect cells. This study aimed to compare the degree of lung injury due to limb IRI in Sprague-Dawley (SD) rats with selenium administration versus those without selenium treatment.

Materials and Methods

: Fifteen male SD rats were divided into three groups: the control group (Group A), the ischemia-reperfusion with pre-reperfusion selenium (Group B), and the ischemia-reperfusion with post-reperfusion selenium (Group C). All animals underwent two hours of limb ischemia and three hours of reperfusion. Selenium was given intravenously at a dose of 0.2 mg/kg body weight. After reperfusion, lung specimens were histopathologically examined.

Results

: The median degree of lung injury was severe in Group A, mild in Group B, and moderate in Group C (P=0.01). Post hoc analysis revealed a significant difference in the degree of lung injury between Groups A and B (P=0.01), while a comparison between Groups A and C (P=0.06) and Groups B and C (P=0.31) revealed no significant difference.

Conclusion

: The administration of pre-reperfusion selenium significantly decreases lung injury induced by limb ischemia-reperfusion in SD rats.

Drug delivery nanosystems targeted to hepatic ischemia and reperfusion injury

Hepatic ischemia and reperfusion injury (IRI) is an acute inflammatory process that results from surgical interventions, such as liver resection surgery or transplantation, or hemorrhagic shock. This pathology has become a severe clinical issue, due to the increasing incidence of hepatic cancer and the high number of liver transplants. So far, an effective treatment has not been implemented in the clinic. Despite its importance, hepatic IRI has not attracted much interest as an inflammatory disease, and only a few reviews addressed it from a therapeutic perspective with drug delivery nanosystems. In the last decades, drug delivery nanosystems have proved to be a major asset in therapy because of their ability to optimize drug delivery, either by passive or active targeting. Passive targeting is achieved through the enhanced permeability and retention (EPR) effect, a main feature in inflammation that allows the accumulation of the nanocarriers in inflammation sites, enabling a higher efficacy of treatment than conventional therapies. These systems also can be actively targeted to specific compounds, such as inflammatory markers and overexpressed receptors in immune system intermediaries, allowing an even more specialized therapy that have already showed encouraging results. In this manuscript, we review drug delivery nanosystems designed for hepatic IRI treatment, addressing their current state in clinical trials, discussing the main hurdles that hinder their successful translation to the market and providing some suggestions that could potentially advance their clinical translation.

Effects of grape seed proanthocyanidin B2 pretreatment on oxidative stress and renal tubular epithelial cell apoptosis after renal ischemia reperfusion in mice

PURPOSE

To investigate the effects of grape seed proanthocyanidin B2 (GSPB2) preconditioning on oxidative stress and apoptosis of renal tubular epithelial cells in mice after renal ischemia-reperfusion (RIR).

METHODS

Forty male ICR mice were randomly divided into 4 groups: Group A: mice were treated with right nephrectomy. Group B: right kidney was resected and the left renal vessel was clamped for 45 minutes. Group C: mice were intraperitoneally injected with GSPB2 before RIR established. Group D: mice were intraperitoneally injected with GSPB2 plus brusatol before RIR established. Creatinine and urea nitrogen of mice were determined. Pathological and morphological changes of kidney were checked. Expressions of Nrf-2, HO-1, cleaved-caspase3 were detected by Western-blot.

RESULTS

Compared to Group B, morphology and pathological damages of renal tissue were less serious in Group C. Western-blot showed that expressions of Nrf-2 and HO-1 in Group C were obviously higher than those in Group B. The expression of cleaved-caspase3 in Group C was significantly lower than that in Group B.

CONCLUSION

GSPB2 preconditioning could attenuate renal oxidative stress injury and renal tubular epithelial cell apoptosis by up-regulating expressions of Nrf-2 and HO-1 and down-regulating the expression of cleaved-caspase-3, but the protective effect could be reversed by brusatol.

Novel Targets for Treating Ischemia-Reperfusion Injury in the Liver

Liver ischemia-reperfusion injury (IRI) is a major complication of hemorrhagic shock, liver transplantation, and other liver surgeries. It is one of the leading causes for post-surgery hepatic dysfunction, always leading to morbidity and mortality. Several strategies, such as low-temperature reperfusion and ischemic preconditioning, are useful for ameliorating liver IRI in animal models. However, these methods are difficult to perform in clinical surgeries. It has been reported that the activation of peroxisome proliferator activated receptor gamma (PPARγ) protects the liver against IRI, but with unidentified direct target gene(s) and unclear mechanism(s). Recently, FAM3A, a direct target gene of PPARγ, had been shown to mediate PPARγ’s protective effects in liver IRI. Moreover, noncoding RNAs, including LncRNAs and miRNAs, had also been reported to play important roles in the process of hepatic IRI. This review briefly discussed the roles and mechanisms of several classes of important molecules, including PPARγ, FAM3A, miRNAs, and LncRNAs, in liver IRI. In particular, oral administration of PPARγ agonists before liver surgery or liver transplantation to activate hepatic FAM3A pathways holds great promise for attenuating human liver IRI.