Ischemia-reperfusion Apoptosis Research Articles

MORIN, A BIOFLAVONOID, ATTENUATES MYOCARDIAL ISCHEMIA-REPERFUSION INJURY BY ATTENUATING RISK/SAPK PATHWAY

Objective: It is important to address the impact of rising incidence of mortality and morbidity associated with myocardial infarction (MI). There is need to explore new safer and efficacious drugs with novel mechanisms to manage MI. Morin, (2-(2,4-Dihydroxyphenyl)-3, is a bioflavanoid which is found in Maclura cochinchinensis, Maclura tinctoria, Maclura pomifera and leaves of Psidium guajava. It possesses good anti-apoptotic, anti-inflammatory, and antioxidant activity. Hence, we have evaluated the cardio-protective effect of Morin in Myocardial Ischemia-Reperfusion (IR) injury model of rat. Design and method: Male albino Wistar rats were pre-treated with Morin (40 and 80 mg/kg; p.o.) for 28 days and on the 29th day, the chest cavity was opened and myocardial ishemia was induced for 45 minutes by ligatiing the LAD coronary artery. Thereafter, reperfusion was carried out for 60 minutes. The hemodynamic parameters as well as left ventricular pressures (±LV dp/dt and LVEDP) were recorded throughout the ischemia and reperfusion. At the end of the procedure, the blood and heart were collected for evaluation of cardiac-injury markers, antioxidant-oxidant parameters, inflammatory markets, histopathological evaluation and molecular signalling pathway protein expressions. Results: Morin pretreatment for 28 days at 40 mg/kg and 80 mg/kg doses significantly controlled hemodynamic parameters, reduced cardiac injury markers, inflammation and apoptosis and reduced oxidative stress and mitigated histological changes following IR injury in rat heart. Morin also downregulated expression of pro-inflammatory and pro-apoptotic SAPK pathway proteins (p38 and JNK), and upregulated the survival kinase protein expression i.e. RISK pathway (ERK, eNOS). Conclusions: Morin reduced myocardial oxidative stress, inflammation and apoptosis in ischemia-reperfusion induced cardiac injury through upregulation of RISK and downregulation of SAPK pathways proteins.

Mitochondria-Targeted Antioxidant Mitoquinone Maintains Mitochondrial Homeostasis through the Sirt3-Dependent Pathway to Mitigate Oxidative Damage Caused by Renal Ischemia/Reperfusion.

Mitochondrial dysfunction is a critical factor contributing to oxidative stress and apoptosis in ischemia-reperfusion (I/R) diseases. Mitoquinone (MitoQ) is a mitochondria-targeted antioxidant whose potent anti-I/R injury capacity has been demonstrated in organs such as the heart and the intestine. In the present study, we explored the role of MitoQ in maintaining mitochondrial homeostasis and attenuating oxidative damage in renal I/R injury. We discovered that the decreased renal function and pathological damage caused by renal I/R injury were significantly ameliorated by MitoQ. MitoQ markedly reversed mitochondrial damage after I/R injury and inhibited renal reactive oxygen species production. In vitro, hypoxia/reoxygenation resulted in increased mitochondrial fission and decreased mitochondrial fusion in human renal tubular epithelial cells (HK-2), which were partially prevented by MitoQ. MitoQ treatment inhibited oxidative stress and reduced apoptosis in HK-2 cells by restoring mitochondrial membrane potential, promoting ATP production, and facilitating mitochondrial fusion. Deeply, renal I/R injury led to a decreased expression of sirtuin-3 (Sirt3), which was recovered by MitoQ. Moreover, the inhibition of Sirt3 partially eliminated the protective effect of MitoQ on mitochondria and increased oxidative damage. Overall, our data demonstrate a mitochondrial protective effect of MitoQ, which raises the possibility of MitoQ as a novel therapy for renal I/R.

Micro RNA-320 as a novel potential biomarker in renal ischemia reperfusion

Aim: MicroRNAs (miR) are important diagnostic and treatment targets due to their different tissue expressions and their central position in the regulation of gene expressions. miR studies might pioneer emerging of new diagnostic tools and treatment goals in kidney diseases. Captopril (CAP) and telmisartan (TEL) were shown to be effective in ischemia reperfusion (IR) injury. There is not any study about the effect of TEL and CAP over miR-21-320-146a. Our aim was to study the effects of CAP and TEL over miR on renal IR model.Methods: We used 12–16 weeks-old Wistar-Albino rats that weigh 300–350 g. Rats (n, 6) were randomized into four groups (Control, IR, IR + CAP, IR + TEL). Urea, creatinine, total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), super oxide dismutase (SOD), and miRs were analyzed.Results: Urea, creatinine, TOS, OSI levels of IR + CAP, and IR + TEL groups were lower comparing to IR group. TAS and SOD levels were higher in IR group than IR + TEL group. miR-21-320-146a showed increase in renal IR injury. miR-320, 146a showed significant decrease in IR + CAP and IR + TEL groups comparing to IR group. We showed histopathological recovery and decreased apoptosis in IR + CAP and IR + T groups than IR group.Conclusion: We, for the first time in the literature, showed that miR-320 is increased in IR injury. miR-320 might be a novel diagnosis and treatment target in renal ischemic reperfusion injury. Also, for the first time, we showed that CAP and TEL cause functional and histopathological recovery and lower miR-146a and miR-320.

Nafamostat Mesilate Attenuates Ischemia-Reperfusion-Induced Renal Injury.

It has been reported that nafamostat mesilate (NM) inhibits inflammatory injury via inhibition of complement activation in ischemic heart, liver, and intestine. However, it is unclear if NM also inhibits apoptosis in ischemia-reperfusion (IR)-injured kidney. We therefore investigated whether NM attenuates IR renal injury that involves inhibition of apoptosis. HK-2 cells and male C57BL/6 mice were used for this study. C57Bl/6 mice were divided into 4 groups: sham, NM (2mg/kg)+ sham, IR injury (IR injury; reperfusion 27 minutes after clamping of both the renal artery and vein), and NM+ IR injury. Kidneys were harvested 24 hours after IR injury, and functional and molecular parameters were evaluated. For invitro studies, HK-2 cells were incubated for 6 hours with mineral paraffin oil to induce hypoxic injury, and then treated with various doses of NM to evaluate the antiapoptotic effects. Blood urea nitrogen, serum creatinine levels, and renal tissue injury scores in NM+ IR-injured mice were significantly lower than those of control IR mice (all P< .01). NM significantly improved cell survival in hypoxic HK-2 cells (P< .01), significantly decreased renal Bax expression (P< .05), and increased renal Bcl-2 protein levels in IR kidneys and hypoxic HK-2 cells compared with those of the sham and control groups. The numbers of terminal deoxynucleotide transferase-mediated dUTP nick-end labeling- and 8-oxo-2'-deoxyguanosine-positive cells were significantly lower in NM+ IR-injured kidneys compared with those in control IR-injured mice (P< .05); NM treatment decreased the expression of inducible and endothelial nitric oxide synthase in IR-injured mice (P< .05). NM ameliorates IR renal injury via inhibition of apoptosis by, at least in part, lowering nitric oxide overproduction, reducing Bax, and increasing Bcl-2.

Mitochondria-Derived Superoxide Links to Tourniquet-Induced Apoptosis in Mouse Skeletal Muscle

Our previous study has reported that superoxide mediates ischemia-reperfusion (IR)-induced necrosis in mouse skeletal muscle. However, it remains poorly understood whether IR induces apoptosis and what factors are involved in IR-induced apoptosis in skeletal muscle. Using a murine model of tourniquet-induced hindlimb IR, we investigated the relationship between mitochondrial dysfunction and apoptosis in skeletal muscle. Hindlimbs of C57/BL6 mice were subjected to 3 h ischemia and 4 h reperfusion via placement and release of a rubber tourniquet at the greater trochanter. Compared to sham treatment, tourniquet-induced IR significantly elevated mitochondria-derived superoxide production, activated opening of mitochondrial permeability transition pore (mPTP), and caused apoptosis in the gastrocnemius muscles. Pretreatment with a superoxide dismutase mimetic (tempol, 50 mg/kg) or a mitochondrial antioxidant (co-enzyme Q10, 50 mg/kg) not only decreased mitochondria-derived superoxide production, but also inhibited mPTP opening and apoptosis in the IR gastrocnemius muscles. Additionally, an inhibitor of mPTP (cyclosporine A, 50 mg/kg) also inhibited both mPTP opening and apoptosis in the IR gastrocnemius muscles. These results suggest that mitochondria-derived superoxide overproduction triggers the mPTP opening and subsequently causes apoptosis in tourniquet-induced hindlimb IR.

Anti-Apoptotic Pro-Survival Effect of Clotrimazole in a Normothermic Ischemia Reperfusion Injury Animal Model

Increasing evidence suggests that apoptosis plays a critical role in ischemia reperfusion (IR)-mediated liver injury. Clotrimazole (CTZ) is a potent antimycotic drug that also has a free radical scavenger activity. This study investigated the possible anti-apoptotic, pro-survival role of CTZ in hepatic IR injury in rats. Male Sprague-Dawley rats were divided into three groups: sham, control, and CTZ-treated (n = 10 each). Control and CTZ-treated animals were subjected to 60 min of normothermic ischemia of the left lateral lobe of the liver followed by 6 h of reperfusion. Animals were then sacrificed, the liver excised, and blood samples collected. CTZ induced a significant increase in expression of anti-apoptotic Bcl-xL protein. Serum levels of aspartate transaminase and alanine transaminase were significantly lower in CTZ-treated animals than in controls. Histopathologically, tissue damage in the form of apoptosis was significantly lower in CTZ-treated animals than in controls. Expression of the activated form of caspase-3 and the cleaved form of its substrate, poly-ADP-ribose polymerase, decreased significantly in the CTZ-treated group compared with controls. CTZ increased the expression of phospho-p 44/42 ERK1/2 and decreased the phosphorylated form of JNK, without affecting p38 MAPK. CTZ protects the liver against IR apoptosis in rats through overexpression of the anti-apoptotic protein Bcl-xL. Other pro-survival pathways such as phospho-p 44/42 ERK1/2 kinase are also activated while JNK is down-regulated.

Effects of leptin on p53 expression and apoptosis in ischemia reperfusion induced renal injury

Effects of leptin on p53 expression and apoptosis in ischemia reperfusion induced renal injury

Clotrimazole Protects the Liver Against Normothermic Ischemia-Reperfusion Injury in Rats

To investigate the possible antiapoptotic prosurvival role of the pregnane X receptor (PXR) in hepatic ischemia-reperfusion injury in rats using clotrimazole (CTZ), a strong PXR transactivator. Male Sprague-Dawley rats were divided into 3 groups of 6 each: sham-treated, control, and CTZ-treated animals. Control and CTZ-treated animals were subjected to 30 minutes of normothermic ischemia of the whole liver followed by 6 hours of reperfusion. The animals were then killed, and the liver was excised and blood samples collected. Clotrimazole induced a significant increase in expression of the CYP3A gene, indicating PXR transactivation, whereas expression of the antiapoptotic Bcl-xL gene was not increased. Serum concentrations of aspartate aminotransaminase and alanine aminotransaminase were lower in CTZ-treated animals than in control animals (difference not significant). Levels of poly(adenosine diphosphate-ribose) polymerase, a caspase-3 substrate, remained significantly higher in the CTZ-treated group compared with controls (P < .05). Clotrimazole increased the expression of phospho-p 44/42 extracellular signal-regulated kinase 1,2 (P < .05). The gene expression of the heat shock proteins 27, 70 and 90 was significantly lower in CTZ-treated animals than in controls (P < .05). Clotrimazole-mediated PXR transactivation protects the liver against ischemia-reperfusion apoptosis in rats. Phospho-p 44/42 extracellular signal-regulated kinase 1,2 is activated, whereas gene expression of heat shock proteins 27, 70, and 90 is downregulated by induction of PXR.

Pretreatment With the Tumor Nerosis Factor-α Blocker Etanercept Attenuated Ischemia-Reperfusion Renal Injury

Tumor necrosis factor (TNF)-alpha mediates inflammation and apoptosis in ischemia-reperfusion (IR) injury of the kidneys. Etanercept, a soluble TNF-alpha receptor, has shown anti-inflammatory and anti-apoptotic effects in several animal models of renal injury, including chronic insufficiency and unilateral ureteral obstruction. We evaluated the protective effect of etanercept against experimental renal IR injury. Male Sprague-Dawley (SD) rats were divided into 4 groups: saline-treated sham rats, etanercept-treated sham rats, saline-treated IR rats, and etanercept-treated IR rats. Renal messenger RNA (mRNA) levels of TNF-alpha and monocyte chemotactic protein-1 (MCP-1) were measured by real-time polymerase chain reaction (PCR) at 24 hours after IR injury. The protein levels of renal Bcl-2 associated X (Bax), B-cell lymphoma 2 (Bcl), extracellular signal-regulated kinase (ERK), and caspase-3 activation were evaluated using Western blot analysis. The degree of apoptosis of renal tubular cells was determined using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays. At 24 hours after IR injury, the serum levels of blood urea nitrogen (BUN) and creatinine were significantly lower among etanercept-treated than saline-treated IR rats. Renal mRNA levels of TNF-alpha and MCP-1 in saline-treated IR rats were significantly higher than the levels in saline-treated sham rats, and TNF-alpha and MCP-1 mRNA levels in etanercept-treated IR rats were significantly lower than those in saline-treated IR rats. Etanercept pretreatment of IR-injured rats significantly increased EKR phosphorylation and reduced the renal Bcl-2/Bax ratio, the renal caspase-3 activation, and the number of TUNEL-positive apoptotic cells. Etanercept improved resistance to renal injury during IR by enhancing the activation of ERK and increasing the Bcl-2/Bax ratio.

The effect of Misoprostol, a prostaglandin E1 analog, on apoptosis in ischemia–reperfusion-induced intestinal injury

The aim of this study was to investigate whether Misoprostol, a synthetic prostaglandin (PG) E1 analog, has any effect on the prevention of apoptosis in ischemia-reperfusion (I/R)-induced intestinal injury. Thirty adult male Wistar albino rats were divided into three groups: group I=sham operated+saline; group II=I/R+saline; and group III=I/R+Misoprostol. Misoprostol (50microg/kg/d) was administered as an intragastric meal for 3 days. The terminal ileum was collected for histological and biochemical investigations. Apoptotic cells were detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelled (TUNEL) reaction. Immunohistochemical analysis was performed to determine the distribution of inducible nitric oxide synthase (iNOS) and endothelial NOS (eNOS). Samples were also analyzed for malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px). The number of TUNEL-positive cells was higher in group II when compared to the other two groups (p<0.05). In group III this value was higher when compared to group I, but lower than group II (p<0.05). iNOS immunoreactivity was not detected in ileum sections of group I animals, but moderate immunoreactivity was seen in group II and mild immunoreactivity in group III. The immunoreactivity of eNOS was moderate in ileum sections of all three groups. In ileum tissue, MDA was found to be higher in group II compared to group I (p<0.05), but there was no difference in group III. SOD was not different between groups I and III, but was significantly higher in group II (p<0.05). In our experimental model of I/R-induced intestinal injury, apoptosis is induced in enterocytes, whereas Misoprostol decreases enterocyte apoptosis in this experimental model. Our results indicate that Misoprostol may play a key role in the pathophysiologic events leading to failure of the intrinsic gut barrier defense mechanisms of intestinal epithelium.