Evaluation of the neuroprotective and antioxidant effects of Dorema aucheri extract on cerebral ischaemia-reperfusion injury in rats

CONTEXT

The hydroalcoholic extract of Dorema aucheri Bilhar (Umbelliferae) (DA) leaves, a medicinal plant, has powerful antioxidant properties.

OBJECTIVE

This study evaluates the neuroprotective effects of pre-treatment with DA leaves extract against cerebral ischaemia-induced brain injury through alteration of the antioxidant capacity.

MATERIALS AND METHODS

The study was conducted in three groups of Wistar rats (N = 47) as follows; sham, control ischaemic and pre-treated ischaemic groups. Rats were administered a fresh hydroalcoholic extract of DA leaves at a dosage of 200 mg/kg/day for 14 days. Then, the middle cerebral artery (MCA) of the right hemisphere was occluded for 90 min to achieve cerebral ischaemia. After 24 h reperfusion, cerebral infarction and superoxide dismutase (SOD) and catalase activities, as well as malondialdehyde (MDA), glutathione, and NOx contents were determined in the right hemispheres.

RESULTS

Occlusion of the right MCA caused noticeable cerebral infarction (298 ± 21 mm³) in control ischaemic group, but pre-treatment with DA extract considerably attenuated it (92 ± 14 mm³) in the pre-treated ischaemic group. DA extract significantly decreased the levels of MDA by 28% and NOx by 11% in pre-treated ischaemic group compared to the control ischaemic group. DA extract also enhanced glutathione content by 7%, SOD activity by 16% and catalase activity by 46% in pre-treated ischaemic rats compared to control ischaemic rats.

DISCUSSION AND CONCLUSIONS

DA is able to improve the antioxidant capacity and injuries of ischaemic brain. It is proposed as a neuroprotectant following cerebral ischaemia to decrease the injuries of ischaemic stroke.

Cyclooxygenase inhibition prior to ventricular fibrillation induced ischemia reperfusion injury impairs survival and outcomes

Nonsteroidal anti-inflammatory medications (NSAIDs) are one of the most commonly used analgesics in the world. NSAIDs decrease prostaglandin synthesis through cyclooxygenase inhibition (COX-1 or COX-2). The effects of NSAIDs on survival and outcomes from global ischemia reperfusion events and specifically from cardiac arrest (CA) remain controversial. We hypothesized that NSAIDs prior to global whole-body ischemia reperfusion (I/R) injury impairs survival and outcomes. We explored this hypothesis in our swine model of Cardiac Arrest (CA) which involves global I/R with pretreatment using a predominantly COX-1 inhibitor (Indomethacin [COX-1/min COX-2 Inh], a COX-2 Inhibitor [COX-2-Inh, (Celecoxib)] or placebo control. We determined the effects of each inhibitor on a) survival, b) myocardial injury biomarker (Troponin 1), and c) Autonomic Nervous System (ANS) injury marker (heart rate variability [HRV]) up to 3 h after resuscitation. There were no survivals in COX-1/min COX-2-Inh pretreated animals and, 87% survived in both COX-2 Inhibited and control animals. COX-2 Inh pretreated animals had an 1800 fold increase of Troponin 1 compared to baseline whereas control animals had a 90 fold increase (p < 0.001). These results along with literature review of focal I/R in animal models with COX-2 overexpression, human studies of CA, and post myocardial infarction treatment with NSAIDs, support the hypothesis that NSAIDs prior to an I/R event impairs survival and outcomes. Specifically, predominantly COX-1 inhibition impairs survival, and COX-2 inhibition induces myocardial damage, autonomic nervous system dysfunction, and increases the risk for all-cause mortality and morbidity in humans post-MI which has significant implications for the nearly 10% of the population who are taking NSAIDs.

Xanthine oxidase inhibitor ameliorates postischemic renal injury in mice by promoting resynthesis of adenine nucleotides

Although oxidative stress plays central roles in postischemic renal injury, region-specific alterations in energy and redox metabolism caused by short-duration ischemia remain unknown. Imaging mass spectrometry enabled us to reveal spatial heterogeneity of energy and redox metabolites in the postischemic murine kidney. After 10-minute ischemia and 24-hour reperfusion (10mIR), in the cortex and outer stripes of the outer medulla, ATP substantially decreased, but not in the inner stripes of the outer medulla and inner medulla. 10mIR caused renal injury with elevation of fractional excretion of sodium, although histological damage by oxidative stress was limited. Ischemia-induced NADH elevation in the cortex indicated prolonged production of reactive oxygen species by xanthine oxidase (XOD). However, consumption of reduced glutathione after reperfusion suggested the amelioration of oxidative stress. An XOD inhibitor, febuxostat, which blocks the degradation pathway of adenine nucleotides, promoted ATP recovery and exerted renoprotective effects in the postischemic kidney. Because effects of febuxostat were canceled by silencing of the hypoxanthine phosphoribosyl transferase 1 gene in cultured tubular cells, mechanisms for the renoprotective effects appear to involve the purine salvage pathway, which uses hypoxanthine to resynthesize adenine nucleotides, including ATP. These findings suggest a novel therapeutic approach for acute ischemia/reperfusion renal injury with febuxostat through salvaging high-energy adenine nucleotides.

Polyethylene glycol-conjugated human adrenomedullin as a possible treatment for vascular dementia

Adrenomedullin (AM) is a multifunctional bioactive peptide. Recent studies have shown that AM has protective effects against ischemic brain damage. We recently prepared a long-acting human AM derivative that was conjugated with a 60 kDa polyethylene glycol (PEG-AM), which had an effect similar to that of native AM. In this study, we examined the effect of PEG-AM on four-vessel occlusion model rats, which exhibit vascular dementia. From day 10 to day 14 after surgery, the learning and memory abilities of the rats were examined using a Morris water maze. The rats were treated with a single subcutaneous injection of 1.0 or 10.0 nmol/kg of PEG-AM. PEG-AM treatment reduced the escape latency in the hidden platform test. Furthermore, the treatment increased the time spent in the platform quadrant in the probe test. The data showed that PEG-AM injection prevented memory loss and learning disorders in dose-dependent manner. On day 14, the immunoreactive AM concentration in plasma was 9.749 ± 2.167 pM in the high-dose group (10.0 nmol/kg) and 0.334 ± 0.073 pM in the low-dose group (1.0 nmol/kg). However, even in the low-dose group, a significant effect was observed in both tests. The present data indicate that PEG-AM is a possible therapeutic agent for the treatment of ischemic brain injury or vascular dementia.

Examining Mannitol Use in Kidney Cancer Surgery: A Cautionary Tale of Extrapolated Surgical Data

Mannitol for renal protection during partial nephrectomy is common but unsupported by evidence from clinical trials. The impact of mannitol on renal physiology includes both beneficial and harmful effects. Current understanding of renal ischemia reperfusion injury suggests potentially targetable processes that have a lower potential risk.

An in Vivo miRNA Delivery System for Restoring Infarcted Myocardium

A major challenge in myocardial infarction (MI)-related heart failure treatment using microRNA is the efficient and sustainable delivery of miRNAs into myocardium to achieve functional improvement through stimulation of intrinsic myocardial restoration. In this study, we established an in vivo delivery system using polymeric nanoparticles to carry miRNA (miNPs) for localized delivery within a shear-thinning injectable hydrogel. The miNPs triggered proliferation of human embryonic stem cell-derived cardiomyocytes and endothelial cells (hESC-CMs and hESC-ECs) and promoted angiogenesis in hypoxic conditions, showing significantly lower cytotoxicity than Lipofectamine. Furthermore, one injected dose of hydrogel/miNP in MI rats demonstrated significantly improved cardiac functions: increased ejection fraction from 45% to 64%, reduced scar size from 20% to 10%, and doubled capillary density in the border zone compared to the control group at 4 weeks. As such, our results indicate that this injectable hydrogel/miNP composite can deliver miRNA to restore injured myocardium efficiently and safely.

Oxidative stress-responsive apoptosis inducing protein (ORAIP) plays a critical role in cerebral ischemia/reperfusion injury

Oxidative stress is known to play a critical role in the pathogenesis of various disorders, especially in ischemia/reperfusion (I/R) injury. We identified an apoptosis-inducing humoral factor and named this novel post translationally modified secreted form of eukaryotic translation initiation factor 5A (eIF5A) "oxidative stress-responsive apoptosis inducing protein" (ORAIP). The purpose of this study was to investigate the role of ORAIP in the mechanisms of cerebral I/R injury. Hypoxia/reoxygenation induced expression of ORAIP in cultured rat cerebral neurons, resulting in extensive apoptosis of these cells, which was largely suppressed by neutralizing anti-ORAIP monoclonal antibody (mAb) in vitro. Recombinant-ORAIP induced extensive apoptosis of cerebral neurons. Cerebral I/R induced expression of ORAIP in many neurons in a rat tandem occlusion model in vivo. In addition, we analyzed the effects of intracerebroventricular administration of neutralizing anti-ORAIP mAb on the development of cerebral infarction. Cerebral I/R significantly increased ORAIP levels in cerebrospinal fluid. Treatment with intracerebroventricular administration of neutralizing anti-ORAIP mAb reduced infarct volume by 72%, and by 55% even when started after reperfusion. These data strongly suggest that ORAIP plays a pivotal role and will offer a critical therapeutic target for cerebral I/R injury induced by thrombolysis and thrombectomy for acute ischemic stroke.

Heme oxygenase-2 protects against ischemic acute kidney injury: influence of age and sex

Heme oxygenase (HO) activity is exhibited by inducible (HO-1) and constitutive (HO-2) proteins. HO-1 protects against ischemic and nephrotoxic acute kidney injury (AKI). We have previously demonstrated that HO-2 protects against heme protein-induced AKI. The present study examined whether HO-2 is protective in ischemic AKI. Renal ischemia was imposed on young and aged HO-2+/+ and HO-2-/- mice. On days 1 and 2 after renal ischemia, there were no significant differences in renal function between young male HO-2+/+ and HO-2-/- mice, between young female HO-2+/+ and HO-2-/- mice, or between aged female HO-2+/+ and HO-2-/- mice. However, in aged male mice, HO-2 deficiency worsened renal function on days 1 and 2 after ischemic AKI, and, on day 2 after ischemia, such deficiency augmented upregulation of injury-related genes and worsened histological injury. Renal HO activity was markedly decreased in unstressed aged male HO-2-/- mice and remained so after ischemia, despite exaggerated HO-1 induction in HO-2-/- mice after ischemia. Such exacerbation of deficiency of HO-2 protein and HO activity may reflect phosphorylated STAT3, as activation of this proinflammatory transcription factor was accentuated early after ischemia in aged male HO-2-/- mice. This exacerbation may not reflect impaired induction of nephroprotectant genes, since the induction of HO-1, sirtuin 1, and β-catenin was accentuated in aged male HO-2-/- mice after ischemia. We conclude that aged male mice are hypersensitive to ischemic AKI and that HO-2 mitigates such sensitivity. We speculate that this protective effect of HO-2 may be mediated, at least in part, by suppression of phosphorylated STAT3-dependent signaling.

Role of carbonic anhydrase in acute recovery following renal ischemia reperfusion injury

Ischemia reperfusion (IR) injury can cause acute kidney injury. It has previously been reported that kidney oxygen consumption (QO2) in relation to glomerular filtration rate (GFR), and thus tubular sodium load, is markedly increased following IR injury, indicating reduced electrolyte transport efficiency. Since proximal tubular sodium reabsorption (TNa) is a major contributor to overall kidney QO2, we investigated whether inhibition of proximal tubular sodium transport through carbonic anhydrase (CA) inhibition would improve renal oxygenation following ischemia reperfusion. Anesthetized adult male Sprague Dawley rats were administered the CA inhibitor acetazolamide (50 mg/kg bolus iv), or volume-matched vehicle, and kidney function, hemodynamics and QO2 were estimated before and after 45 minutes of unilateral complete warm renal ischemia. CA inhibition per se reduced GFR (-20%) and TNa (-22%), while it increased urine flow and urinary sodium excretion (36-fold). Renal blood flow was reduced (-31%) due to increased renal vascular resistance (+37%) without affecting QO2. IR per se resulted in similar decrease in GFR and TNa, independently of CA activity. However, the QO2/TNa ratio following ischemia-reperfusion was profoundly increased in the group receiving CA inhibition, indicating a significant contribution of basal oxygen metabolism to the total kidney QO2 following inhibition of proximal tubular function after IR injury. Ischemia increased urinary excretion of kidney injury molecule-1, an effect that was unaffected by CA. In conclusion, this study demonstrates that CA inhibition further impairs renal oxygenation and does not protect tubular function in the acute phase following IR injury. Furthermore, these results indicate a major role of the proximal tubule in the acute recovery from an ischemic insult.

Rutaecarpine may improve neuronal injury, inhibits apoptosis, inflammation and oxidative stress by regulating the expression of ERK1/2 and Nrf2/HO-1 pathway in rats with cerebral ischemia-reperfusion injury

BACKGROUND

Cerebral ischemia-reperfusion (CI/R) injury is a more serious brain injury caused by the recovery of blood supply after cerebral ischemia for a certain period of time. Rutaecarpine (Rut) is an alkaloid isolated from Evodia officinalis with various biological activities. Previous studies have shown that Rut has a certain protective effect on ischemic brain injury, but the specific molecular mechanism is still unknown.

METHODS

In this study, a rat model of CI/R was established to explore the effects and potential molecular mechanisms of Rut on CI/R injury in rats.

RESULTS

The results showed that Rut alleviated neuronal injury induced by CI/R in a dose-dependent manner. Besides, Rut inhibited neuronal apoptosis by inhibiting the activation of caspase 3 and the expression of Bax. In addition, Rut alleviated the inflammatory response and oxidative stress caused by CI/R through inhibiting the production of pro-inflammatory factors (IL-6 and IL-1β), lactate dehydrogenase (LDH), malondialdehyde (MDA) and ROS, and increased the levels of anti-inflammatory factors (IL-4 and IL-10) and superoxide dismutase (SOD). Biochemically, Western blot analyses showed that Rut inhibited the phosphorylation of ERK1/2 and promoted the expression of nuclear factor-erythroid 2 related factor 2 (Nrf2) pathway-related proteins (Nrf2, heme oxygenase 1 (HO-1) and NAD (P) H-quinone oxidoreductase 1) in a dose-dependent manner. These results show that Rut may alleviate brain injury induced by CI/R by regulating the expression of ERK1/2 and the activation of Nrf2/HO-1 pathway.

CONCLUSION

In conclusion, these results suggest that Rut may be used as an effective therapeutic agent for damage caused by CI/R.

N-acetyl-l-cysteine exacerbates kidney dysfunction caused by a chronic high-sodium diet in renal ischemia and reperfusion rats

AIMS

To investigate the effect of long-term N-acetyl-l-cysteine (NAC) treatment in Wistar rats subjected to renal ischemia and reperfusion (IR) and a chronic high‑sodium diet (HSD).

MAIN METHODS

Adult male Wistar rats received an HSD (8.0% NaCl) or a normal‑sodium diet (NSD; 1.3% NaCl) and NAC (600 mg/L) or normal drinking water starting at 8 weeks of age. At 11 weeks of age, the rats from both diet and NAC or water treatment groups underwent renal IR or Sham surgery and were followed for 10 weeks. The study consisted of six animal groups: NSD + Sham + water; NSD + IR + water; NSD + IR + NAC; HSD + Sham + water; HSD + IR + water; and HSD + IR + NAC.

KEY FINDINGS

Tail blood pressure (tBP) increased with IR and NAC treatment in the NSD group but not in the HSD group. The serum creatinine level was higher after NAC treatment in both diet groups, and creatinine clearance was decreased in only the HSD + IR + NAC group. Albuminuria increased in the HSD + IR + water group and decreased in the HSD + IR + NAC group. Kidney mass was increased in the HSD + IR group and decreased with NAC treatment. Renal fibrosis was prevented with NAC treatment and cardiac fibrosis was decreased with NAC treatment in the HSD + IR group.

SIGNIFICANCE

NAC treatment promoted structural improvements, such as decreased albuminuria and fibrosis, in the kidney and heart. However, NAC could not recover kidney function or blood pressure from the effects of IR associated with an HSD. Therefore, in general, long-term NAC treatment is not effective and is deleterious to recovery of function after kidney injury.

Ripk3 mediates cardiomyocyte necrosis through targeting mitochondria and the JNK-Bnip3 pathway under hypoxia-reoxygenation injury

Context: Cardiomyocyte necrosis following myocardial infarction drastically the progression of heart failure.Objective: In the current study, we explored the upstream mediator for cardiomyocytes necrosis induced by hypoxia-reoxygenation (HR) injury with a focus on mitochondrial function and JNK-Bnip3 pathway.Materials and methods: Cell necrosis was determined via MTT assay, TUNEL staining and PI staining. siRNA transfection was performed to inhibit Ripk3 activation in response to HR injury. Pathway blocker was applied to prevent JNK activation.Results: Ripk3 was rapidly increased in HR-treated cardiomyocytes and correlated with the necrosis of cardiomyocytes. Interestingly, silencing of Ripk3 attenuated HR-mediated cardiomyocytes necrosis. At the molecular levels, Ripk3 deletion sustained mitochondrial bioenergetics and stabilized mitochondrial glucose metabolism. Besides, Ripk3 deletion also reduced mitochondrial oxidative stress and inhibited mPTP opening. To the end, we found Ripk3 activation was along with JNK pathway activation and Bnip3 upregulation. Interestingly, blockade of JNK pathway abolished the harmful effects of HR injury on mitochondrial function, energy metabolism and redox balance. Moreover, overexpression of Bnip3 abrogated the protection action played by Ripk3 deletion on cardiomyocytes survival.Conclusions: Taken together, these data may identify Ripk3 upregulation, mitochondrial dysfunction and JNK-Bnip3 axis activation as the novel mechanisms underlying cardiomyocytes necrosis achieved by HR injury. Thereby, approaches targeted to the Ripk3-JNK-Bnip3-mitochondria cascade have the potential to ameliorate the progression of HR-related cardiomyocytes necrosis in the clinical practice.

New mouse model of chronic kidney disease transitioned from ischemic acute kidney injury

Acute kidney injury (AKI) significantly increases the risk of development of chronic kidney disease (CKD), which is closely associated with the severity of AKI. However, the underlying mechanisms for the AKI to CKD transition remain unclear. Several animal models with AKI to CKD transition have been generated and widely used in research; however, none of them exhibit the typical changes in glomerular filtration rate or plasma creatinine, the hallmarks of CKD. In the present study, we developed a novel model with a typical phenotype of AKI to CKD transition in C57BL/6 mice. In this model, life-threatening ischemia-reperfusion injury was performed in one kidney, whereas the contralateral kidney was kept intact to maintain animal survival; then, after 2 wk of recovery, when the renal function of the injured kidney restored above the survival threshold, the contralateral intact kidney was removed. Animals of this two-stage unilateral ischemia-reperfusion injury model with pedicle clamping of 21 and 24 min exhibited an incomplete recovery from AKI and subsequent progression of CKD with characteristics of a progressive decline in glomerular filtration rate, increase in plasma creatinine, worsening of proteinuria, and deleterious histopathological changes, including interstitial fibrosis and glomerulosclerosis. In conclusion, a new model of the AKI to CKD transition was generated in C57BL/6 mice.

The cardioprotective effects of diallyl trisulfide on diabetic rats with ex vivo induced ischemia/reperfusion injury

Diallyl trisulfide (DATS) is distinguished as the most potent polysulfide isolated from garlic. The aim of our study was to investigate effects of oral administration of DATS on healthy and diabetic rats, with special attention on heart function. Rats were randomly divided into four groups: CTRL (healthy rats), DATS (healthy rats treated with DATS), DM (diabetic rats), DM + DATS (diabetic rats treated with DATS). DATS (40 mg/kg of body weight) was administered every other day for 3 weeks, at the end of which rats underwent echocardiography, glycemic measurement and redox status assessment. Isolated rat hearts were subjected to 30 min global ischemia and 60 min reperfusion, after which heart tissue was counterstain with hematoxylin and eosin and cardiac Troponin T staining (cTnT), while expression of Bax, B cell lymphoma 2 (Bcl-2), caspase-3, caspase-9 and superoxide dismutase-2 were examined in the left ventricle. DATS treatment significantly reduced blood glucose levels of diabetic rats, and improved cardiac function recovery, diminished oxidation status, attenuated cardiac remodeling and inhibited myocardial apoptosis in healthy and diabetic rats. DATS treatment causes promising cardioprotective effects on ex vivo-induced ischemia/reperfusion (I/R) injury in diabetic and healthy rat heart probably mediated by inhibited myocardial apoptosis. Moreover, appropriate DATS consumption may provide potential co-therapy or prevention of hyperglycemia and various cardiac complications in rats with DM.

Single Muscle Fibre Contractility Testing in Rats to Quantify Ischaemic Muscle Damage During Reperfusion Injury

OBJECTIVES

In this study, the aim was to investigate the potential for single muscle fibre contractility (SMFC) testing to detect the extent of reperfusion injury following various reperfusion periods. The hypothesis was that force generated by muscle fibres will correlate inversely with the extent of reperfusion injury.

METHODS

Twenty-four Lewis rats were distributed among five groups. Group 1 served as normal muscle control. In all other groups, femoral artery flow was occluded for four hours. Muscle biopsies were obtained at 0 hour, six hours, day two, and day seven after reperfusion in Groups 2, 3, 4, and 5, respectively. Samples then underwent ultrastructural analysis (H&E stain) and SMFC testing.

RESULTS

The maximum isometric force (mN) generated on Days two and seven after reperfusion decreased from baseline by 21% (p < 0.05), and 53% (p < .001), respectively. The specific force (kPa) followed a similar pattern with a 13% decrease at Day two (p > 0.05) and 31% decrease at Day 7 (p < .001). These results correlated inversely with the extent of quantitative injury on histology.

CONCLUSIONS

The study demonstrated an inverse relationship between single muscle fibre contractility testing and neutrophil infiltration during the reperfusion phase. Further clinical studies are needed to evaluate its potential in providing prognostic information for patient outcomes.

Gene deletion of the Na+-glucose cotransporter SGLT1 ameliorates kidney recovery in a murine model of acute kidney injury induced by ischemia-reperfusion

Renal Na+-glucose cotransporter SGLT1 mediates glucose reabsorption in the late proximal tubule, a hypoxia-sensitive tubular segment that enters the outer medulla. Gene deletion in mice (Sglt1-/-) was used to determine the role of the cotransporter in acute kidney injury induced by ischemia-reperfusion (IR), including the initial injury and subsequent recovery phase. On days 1 and 16 after IR, absolute and fractional urinary glucose excretion remained greater in Sglt1-/- mice versus wild-type (WT) littermates, consistent with a sustained contribution of SGLT1 to tubular glucose reabsorption in WT mice. Absence of SGLT1 did not affect the initial kidney impairment versus WT mice, as indicated by similar increases on day 1 in plasma concentrations of creatinine and urinary excretion of the tubular injury marker kidney injury molecule-1 as well as a similar rise in plasma osmolality and fall in urine osmolality as indicators of impaired urine concentration. Recovery of kidney function on days 14/16, however, was improved in Sglt1-/- versus WT mice, as indicated by lower plasma creatinine, higher glomerula filtration rate (by FITC-sinistrin in awake mice), and more completely restored urine and plasma osmolality. This was associated with a reduced tubular injury score in the cortex and outer medulla, better preserved renal mRNA expression of tubular transporters (Sglt2 and Na+-K+-2Cl- cotransporter Nkcc2), and a lesser rise in renal mRNA expression of markers of injury, inflammation, and fibrosis [kidney injury molecule-1, chemokine (C-C motif) ligand 2, fibronectin 1, and collagen type I-α1] in Sglt1-/- versus WT mice. These results suggest that SGLT1 activity in the late proximal tubule may have deleterious effects during recovery of IR-induced acute kidney injury and identify SGLT1 as a potential therapeutic target.

Does ischemia reperfusion affect fecundability in a rat model?

BACKGROUND

Adnexal torsion constitutes 2.7% of all gynecological emergencies. Because normal follicular growth has been demonstrated after examination of surgical specimens retrieved from oophorectomies, organ-sparing strategy has gained more popularity irrespective of the appearance of the ovary. However, the functionality of the remaining follicles has not been known. The aim of the study was to evaluate the effect of ischemia-reperfusion on fecundability in a rat model with adnexal torsion.

METHODS

A total of 30 female adult Wistar albino rats were assessed. In the first laparotomy, right ovaries were twisted for 8 (Group I, n = 10) or 24 (Group II, n = 10) hours. Second laparotomy was performed to untwist the torsion side and oophorectomy to the other side. In the control group (Group III, n = 10), left ovaries were removed and right ovaries were kept without any intervention. After 30 days from the last operation, female rats were mated for 10 days and euthanized 4 days later. Fecundability was calculated using beta-human chorionic gonadotropin (hCG) levels for detection of pregnancy rates.

RESULTS

The mean beta-hCG values in control, 8-hour, and 24-hour groups between pregnant rats were 19.8 ± 26.02, 11.7 ± 0.17, and 22.97 ± 11.87 mIU/mL, respectively. Whereas two out of 10 rats (20%) conceived in the 8-hour group, three out of 10 rats (30%) got pregnant in the 24-hour group. In total, whereas five out of the 20 rats got pregnant in the experimental groups, in the control group, seven out of 10 subjects conceived (25% vs 70 %, p = 0.018).

CONCLUSION

Although there was a statistical difference between experimental and control groups, statistical significance was not reached among 8-hour and 24-hour torsion subgroups. In this context, patients with torsion but treated with detorsion should be further investigated for their fecundability potency and be informed accordingly.

Guanine nucleotide-binding protein G(i)α2 aggravates hepatic ischemia-reperfusion injury in mice by regulating MLK3 signaling

Hepatic ischemia-reperfusion (I/R) injury is a major challenge in liver resection and transplantation surgeries. Previous studies have revealed that guanine nucleotide-binding protein G(i)α2 (GNAI2) was involved in the progression of myocardial and cerebral I/R injury, but the role and function of GNAI2 in hepatic I/R have not been elucidated. The hepatocyte-specific GNAI2 knockout (GNAI2hep-/-) mice were generated and subjected to hepatic I/R injury. Primary hepatocytes isolated from GNAI2hep-/- and GNAI2flox/flox mice were cultured and challenged to hypoxia-reoxygenation insult. The specific function of GNAI2 in I/R-triggered hepatic injury and the underlying molecular mechanism were explored by various phenotypic analyses and molecular biology methods. In this study, we demonstrated that hepatic GNAI2 expression was significantly increased in liver transplantation patients and wild-type mice after hepatic I/R. Interestingly, hepatocyte-specific GNAI2 deficiency attenuated I/R-induced liver damage, inflammation cytokine expression, macrophage/neutrophil infiltration, and hepatocyte apoptosis in vivo and in vitro. Mechanistically, up-regulation of GNAI2 phosphorylates mixed-lineage protein kinase 3 (MLK3) through direct binding, which exacerbated hepatic I/R damage via MAPK and NF-κB pathway activation. Furthermore, blocking MLK3 signaling reversed GNAI2-mediated hepatic I/R injury. Our study firstly identifies GNAI2 as a promising target for prevention of hepatic I/R-induced injury and related liver diseases.-Sun, Q., He, Q., Xu, J., Liu, Q., Lu, Y., Zhang, Z., Xu, X., Sun, B. Guanine nucleotide-binding protein G(i)α2 aggravates hepatic ischemia-reperfusion injury in mice by regulating MLK3 signaling.

Ischaemia reperfusion injury: mechanisms of progression to chronic graft dysfunction

The increasing use of extended criteria organs to meet the demand for kidney transplantation raises an important question of how the severity of early ischaemic injury influences long-term outcomes. Significant acute ischaemic kidney injury is associated with delayed graft function, increased immune-associated events and, ultimately, earlier deterioration of graft function. A comprehensive understanding of immediate molecular events that ensue post-ischaemia and their potential long-term consequences are key to the discovery of novel therapeutic targets. Acute ischaemic injury primarily affects tubular structure and function. Depending on the severity and persistence of the insult, this may resolve completely, leading to restoration of normal function, or be sustained, resulting in persistent renal impairment and progressive functional loss. Long-term effects of acute renal ischaemia are mediated by several mechanisms including hypoxia, HIF-1 activation, endothelial dysfunction leading to vascular rarefaction, sustained pro-inflammatory stimuli involving innate and adaptive immune responses, failure of tubular cells to recover and epigenetic changes. This review describes the biological relevance and interaction of these mechanisms based on currently available evidence.

Renal ischemia/reperfusion induced learning and memory deficit in the rat: Insights into underlying molecular and cellular mechanisms

Distance organ dysfunction is the major cause of death in the patients with acute kidney injury (AKI). However, the neurobiological basis of AKI-induced brain disorders and their mediators are poorly understood. This study was aimed to find out the links between AKI and brain injury and also the underlying cellular and electrophysiological mechanisms of memory deficit following induction of AKI via different experimental models of renal ischemia with or without uremia and uremia without renal ischemia. Fifty four male Sprague-Dawley rats were divided into 4 groups that underwent 1-h bilateral or 2-h unilateral renal ischemia followed by 1-day reperfusion (BIR and UIR, respectively), and 1-day following bilateral nephrectomy (BNX) or sham-operation. There were 2 subgroups in each group, which blood-brain barrier (BBB) integrity was evaluated in one subgroup. The other subgroup was used for recordings electrophysiological activities of the hippocampus; and after blood sampling and sacrificing animal, the cerebral hemispheres were removed and preserved for performing stereological study and Western-blotting of caspase-3 in the left and right hippocampus, respectively. Plasma urea and creatinine and CA1 neuronal loss were largely increased by BNX and BIR, but slightly by UIR. Apoptosis was stimulated in the hippocampus intensively by BIR but moderately by UIR and BNX. However, BIR and UIR were associated with profoundly disturbed BBB, increased CA1 neuronal excitability, impaired LTP induction and memory deficit. Therefore, AKI most likely through inflammatory mediators leads to hippocampal apoptosis and electrophysiological impairments, BBB disruption and memory loss, whereas uremia may contribute to necrotic neuronal death.

Alpha lipoic acid attenuates the long-term effects of lead exposure in retinal ischemic injury mouse model

Lead (Pb) exposure is reported to be unsafe for humans. There have been several studies documenting acute and chronic Pb toxicity on the organ systems. New studies suggest that early-life exposure to such environmental toxins may increase the susceptibility to late-onset degenerative disorders. We aimed to examine the long-term effects of early-life postnatal exposure of Pb on retinal degeneration. Pb exposure (200 ppm) was provided either at postnatal day 1 through lactation (early-life exposure) or at 7th week of age (adulthood exposure) directly through drinking water for 20 days. The Pb-treated mice were followed till 20 weeks of age. At 20th week, ischemia/reperfusion (I/R) injury was induced in these mice by pterygopalatine artery ligation. Further, alpha lipoic acid (ALA) was administered to examine its neuroprotective effects against retinal damage. Histological and molecular analysis revealed that Pb-treated mice had greater retinal damage after I/R injury as compared to untreated or ALA treated mice, suggesting that ALA protects the early-life Pb exposure and its consequent impact on later life. The elevated levels of glial derived neurotrophic factor (GDNF) and ciliary neurotrophic factor (CNTF) and reduced levels of glial fibrillary acidic protein (GFAP) upon ALA pre-treatment suggest that it probably exerts anti-inflammatory effects via upregulation of neurotrophic factors.

Detection of Intestinal Tissue Perfusion by Real-Time Breath Methane Analysis in Rat and Pig Models of Mesenteric Circulatory Distress

OBJECTIVES

Methane (CH4) breath test is an established diagnostic method for gastrointestinal functional disorders. Our aim was to explore the possible link between splanchnic circulatory changes and exhaled CH4 in an attempt to recognize intestinal perfusion failure.

DESIGN

Randomized, controlled in vivo animal study.

SETTING

University research laboratory.

SUBJECTS

Anesthetized, ventilated Sprague-Dawley rats (280 ± 30 g) and Vietnamese minipigs (31 ± 7 kg).

INTERVENTIONS

In the first series, CH4 was administered intraluminally into the ileum before 45 minutes mesenteric ischemia or before reperfusion in non-CH4 producer rats to test the appearance of the gas in the exhaled air. In the porcine experiments, the superior mesenteric artery was gradually obstructed during consecutive, 30-minute flow reductions and 30-minute reperfusions achieving complete occlusion after four cycles (n = 6), or nonocclusive mesenteric ischemia was induced by pericardial tamponade (n = 12), which decreased superior mesenteric artery flow from 351 ± 55 to 182 ± 67 mL/min and mean arterial pressure from 96.7 ± 18.2 to 41.5 ± 4.6 mm Hg for 60 minutes.

MEASUREMENTS AND MAIN RESULTS

Macrohemodynamics were monitored continuously; RBC velocity of the ileal serosa or mucosa was recorded by intravital videomicroscopy. The concentration of exhaled CH4 was measured online simultaneously with high-sensitivity photoacoustic spectroscopy. The intestinal flow changes during the occlusion-reperfusion phases were accompanied by parallel changes in breath CH4 output. Also in cardiac tamponade-induced nonocclusive intestinal ischemia, the superior mesenteric artery flow and RBC velocity correlated significantly with parallel changes in CH4 concentration in the exhaled air (Pearson's r = 0.669 or r = 0.632, respectively).

CONCLUSIONS

we report a combination of in vivo experimental data on a close association of an exhaled endogenous gas with acute mesenteric macro- and microvascular flow changes. Breath CH4 analysis may offer a noninvasive approach to follow the status of the splanchnic circulation.

Mitogen Activated Protein Kinases in Steatotic and Non-Steatotic Livers Submitted to Ischemia-Reperfusion

We analyzed the participation of mitogen-activated protein kinases (MAPKs), namely p38, JNK and ERK 1/2 in steatotic and non-steatotic livers undergoing ischemia-reperfusion (I-R), an unresolved problem in clinical practice. Hepatic steatosis is a major risk factor in liver surgery because these types of liver tolerate poorly to I-R injury. Also, a further increase in the prevalence of steatosis in liver surgery is to be expected. The possible therapies based on MAPK regulation aimed at reducing hepatic I-R injury will be discussed. Moreover, we reviewed the relevance of MAPK in ischemic preconditioning (PC) and evaluated whether MAPK regulators could mimic its benefits. Clinical studies indicated that this surgical strategy could be appropriate for liver surgery in both steatotic and non-steatotic livers undergoing I-R. The data presented herein suggest that further investigations are required to elucidate more extensively the mechanisms by which these kinases work in hepatic I-R. Also, further researchers based in the development of drugs that regulate MAPKs selectively are required before such approaches can be translated into clinical liver surgery.

Ischaemia–Reperfusion Injury in the Isolated Haemoperfused Bovine Uterus: An In Vitro Model of Acute Inflammation

Following on from previous studies on dermal inflammation in the isolated perfused bovine udder, a new in vitro model of the isolated haemoperfused bovine uterus was established for studies on acute inflammatory reactions (for example, eicosanoid synthesis and regulation of cyclooxygenase-1 [COX-1] and COX-2) caused by ischaemia-reperfusion (I-R) injury. The organs and blood used in this study were obtained from a slaughterhouse. Within 2 hours of slaughter, uterine perfusion was re-established, by using a mixture of homologous blood and Tyrode solution (4:1). After equilibration, several deposits of arachidonic acid (5 mg and 0.1 mg) and arachidonylethanolamide (0.1 mg) were injected into the myometrial tissue. Tissue biopsies were taken from treated and untreated areas at 180 and 300 minutes after the onset of haemoperfusion, for measuring prostaglandin E(2) (PGE(2)) levels. In addition, the regulation of COX-1 and COX-2 mRNA was investigated by using the reverse transcriptase-polymerase chain reaction. Eicosanoid levels were determined by using an enzyme immunoassay (ELISA). Because both an increase in PGE(2) concentration and up-regulation of COX mRNA were observed, the inhibitory effects of dexamethasone, added to the perfusion medium, were studied. Dexamethasone caused a significant decrease in tissue PGE(2) production, but did not induce down-regulation of COX-2 mRNA. In conclusion, the isolated haemoperfused bovine uterus was introduced as an in vitro model of acute inflammation, induced by I-R injury. The suitability of the model for investigating anti-inflammatory substances was demonstrated. Use of the isolated haemoperfused bovine uterus in pharmacological research and drug screening may contribute to reducing the number of animals used for testing.