Octreotide Ameliorates Renal Ischemia/Reperfusion Injury via Antioxidation and Anti-inflammation

Activation of the SST-SSTR5 signaling pathway enhances corneal wound healing in diabetic mice

Corneal wound healing in diabetic patients is usually delayed and accompanied by excessive inflammation. However, the underlying cellular and molecular mechanisms remain poorly understood. Here, we found that somatostatin (SST), an immunosuppressive peptide produced by corneal nerve fibers, was significantly reduced in streptozotocin-induced diabetic mice. In addition, we discovered that topical administration of exogenous SST significantly improved re-epithelialization and nerve regeneration following diabetic corneal epithelial abrasion. Further analysis showed that topical SST significantly reduced the expression of injury inflammation-related genes, inhibited neutrophil infiltration, and shifted macrophage polarization from pro-inflammatory M1 to anti-inflammatory M2 in diabetic corneas' healing. Moreover, the application of L-817,818, an agonist of the SST receptor type 5 subtype, significantly reduced the inflammatory response following epithelial injury and markedly improved the process of re-epithelialization and nerve regeneration in mice. Taken together, these data suggest that activation of the SST-SST receptor type 5 pathway significantly ameliorates diabetes-induced abnormalities in corneal wound repair in mice. Targeting this pathway may provide a novel strategy to restore impaired corneal wound closure and nerve regeneration in diabetic patients.

Ganoderic Acids Prevent Renal Ischemia Reperfusion Injury by Inhibiting Inflammation and Apoptosis

Renal ischemia reperfusion injury (RIRI) is one of the main causes of acute kidney injury (AKI), which can lead to acute renal failure. The development of RIRI is so complicated that it involves many factors such as inflammatory response, oxidative stress and cell apoptosis. Ganoderic acids (GAs), as one of the main pharmacological components of Ganoderma lucidum, have been reported to possess anti-inflammatory, antioxidant, and other pharmacological effects. The study is aimed to investigate the protective effect of GAs on RIRI and explore related underlying mechanisms. The mechanisms involved were assessed by a mouse RIRI model and a hypoxia/reoxygenation model. Compared with sham-operated group, renal dysfunction and morphological damages were relieved markedly in GAs-pretreatment group. GAs pretreatment could reduce the production of pro-inflammatory factors such as IL-6, COX-2 and iNOS induced by RIRI through inhibiting TLR4/MyD88/NF-kB signaling pathway. Furthermore, GAs reduced cell apoptosis via the decrease of the ratios of cleaved caspase-8 and cleaved caspase-3. The experimental results suggest that GAs prevent RIRI by alleviating tissue inflammation and apoptosis and might be developed as a candidate drug for preventing RIRI-induced AKI.

Activation of Nrf2 Pathway by Dimethyl Fumarate Attenuates Renal Ischemia-Reperfusion Injury

BACKGROUND

Dimethyl fumarate (DMF) is a novel antioxidant that selectively reduces hydroxyl radicals. This study aimed to investigate the potential role of DMF in the pathogenesis of renal ischemia-reperfusion injury (IRI) and the mechanisms involved.

METHODS

C57BL/6 wild-type mice were treated with DMF or a vehicle. Subsequently, renal IRI was induced in mice by a model of right kidney nephrectomy and left renal ischemia for 30 minutes followed by reperfusion for 24 hours. Sham operation and phosphate-buffered saline were used as controls. Serum and renal tissues were collected at 24 hours after IRI to evaluate the influence of DMF on the recovery of renal function after IRI. Blood urea nitrogen and serum creatinine levels were measured. Kidney cell apoptosis was evaluated using terminal deoxynucleotidyl transferase dUTP nick end labeling-positive staining. Interleukin 6 and tumor necrosis factor α cytokines in the kidney tissues were measured. Indicators of oxidative stress in the kidneys were detected. Finally, Nrf2-deficient mice were used to determine the protective role of the nuclear factor erythroid 2-related factor 2 (Nrf2)/hemeoxygenase-1 (HO-1) and NAD(P)H dehydrogenase quinone 1 (NQO1) signaling pathways induced by DMF using western blot assay.

RESULTS

DMF significantly attenuated renal dysfunction in mice and showed reductions in the severity of renal tubular injury, cell necrosis, and apoptosis. Moreover, DMF significantly reduced the amount of key inflammatory mediators. Additionally, DMF attenuated the malondialdehyde levels 24 hours after IRI but upregulated the superoxide dismutase activities. Western blot assay showed that DMF significantly increased the protein levels of Nrf2, HO-1, and NQO-1. Importantly, these DMF-mediated beneficial effects were not observed in Nrf2-deficient mice.

CONCLUSIONS

DMF attenuates renal IRI by reducing inflammation and upregulating the antioxidant capacity, which may be through Nrf2/HO-1and NQO1 signaling pathway.

Beneficial effects of octreotide in alcohol-induced neuropathic pain. Role of H 2S, BDNF, TNF-α and Nrf2

Purpose

To explore the role and molecular mechanisms of neuroprotective effects of octreotide in alcohol-induced neuropathic pain.

Methods

Male Wistar rats were employed and were administered a chronic ethanol diet containing 5% v/v alcohol for 28 days. The development of neuropathic pain was assessed using von Frey hair (mechanical allodynia), pinprick (mechanical hyperalgesia) and cold acetone drop tests (cold allodynia). The antinociceptive effects of octreotide (20 and 40 µg·kg^–1) were assessed by its administration for 28 days in ethanol-treated rats. ANA-12 (0.25 and 0.50 mg·kg^–1), brain-derived neurotrophic factor (BDNF) receptor blocker, was coadministered with octreotide. The sciatic nerve was isolated to assess the biochemical changes including hydrogen sulfide (H₂S), cystathionine β synthase (CBS), cystathionine γ lyase (CSE), tumor necrosis factor-α (TNF-α), BDNF and nuclear factor erythroid 2-related factor 2 (Nrf2).

Results

Octreotide significantly attenuated chronic ethanol-induced neuropathic pain and it also restored the levels of H₂S, CBS, CSE, BDNF, Nrf2 and decreased TNF-α levels. ANA-12 abolished the effects of octreotide on pain, TNF-α, BDNF, Nrf2 without any significant effects on H₂S, CBS, CSE.

Conclusions

Octreotide may attenuate the behavioral manifestations of alcoholic neuropathic pain, which may be due to an increase in H₂S, CBS, CSE, BDNF, Nrf2 and a decrease in neuroinflammation.

The targets of β-sitosterol as a novel therapeutic against cardio-renal complications in acute renal ischemia/reperfusion damage

This research is the first to use β-sitosterol on myocardial and renal tissues in renal ischemia/reperfusion (IR) damage. Female Wistar rats were randomly divided into three groups: control (sham), renal IR (50 min ischemia - 3 h reperfusion), and renal IR + 150 mg/kg/p.o. β-sitosterol (the rats were treated with β-sitosterol orally once 1 h before the IR procedure). β-Sitosterol pretreatment caused an increase in superoxide dismutase and glutathione activities and a decrease in malondialdehyde levels in the kidney and heart. Moreover, it alleviated histopathological changes and downregulated the levels of tumor necrosis factor-alpha and interleukin-6 and upregulated the levels of endothelial nitric oxide synthase. As conclusion, the potential of β-sitosterol for renal and cardiac necrosis and apoptosis appears to act by limiting inflammatory response and oxidative stress. Thus, the potential of this compound is noteworthy and may serve as a potential therapeutic in the treatment of acute organ damages due to renal IR.

Targeting autophagy to modulate hepatic ischemia/reperfusion injury: A comparative study between octreotide and melatonin as autophagy modulators through AMPK/PI3K/AKT/mTOR/ULK1 and Keap1/Nrf2 signaling pathways in rats

Hepatic ischemia-reperfusion (HIR) injury is a common pathophysiological process in many clinical settings. This study was designed to compare the protective role of octreotide (somatostatin analogue, OCT) and melatonin (N-acetyl-5-methoxytryptamine, MLT) through the modulation of autophagy against HIR injury in rats. Male albino rats were divided into sham, HIR, OCT at three doses (50, 75, and 100 μg/kg), MLT, MLT + OCT75, compound C (AMPK inhibitor, CC), and CC + OCT75 groups. Ischemia was induced for 30 min followed by 24 h reperfusion. Biochemical, histopathological, immunohistochemical, lipid peroxidation, ELISA, qPCR, and western blot techniques were performed in our study. Liver autophagy was restored by OCT at doses (50 or 75 μg/kg) as indicated by elevating the expressions of Beclin-1, ATG7, and LC3 accompanied by the reduction of p62 expression through induction of AMPK/S317-ULK1 and inhibition of PI3K/AKT/mTOR/S757-ULK1 signaling pathways. As well, OCT maintained the integrity of the Keap1-Nrf2 system for the normal hepatic functions via controlling the Keap1 turnover through autophagy in a p62-dependent manner, resulting in upholding a series of anti-oxidant and anti-inflammatory cascades. These effects were abolished by compound C. On the other hand, MLT showed a decrease in the autophagy markers via inhibiting AMPK/pS317-ULK1 and activating PI3K/AKT/mTOR/pS757-ULK1 pathways. Autophagy inhibition with MLT markedly reversed the hepatoprotective effects of OCT75 after HIR injury. Finally, our results proved for the first time that OCT75 was more effective than MLT as it was sufficient to induce protective autophagy in our HIR model, which led to the induction of Nrf2-dependent AMPK/autophagy pathways.

Octreotide and melatonin alleviate inflammasome-induced pyroptosis through inhibition of TLR4-NF-κB-NLRP3 pathway in hepatic ischemia/reperfusion injury

BACKGROUND AND AIM

The Toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB)/NLRP3 inflammasome signaling pathway is essential in the pathogenesis of hepatic ischemia/ reperfusion (HIR) injury. Pyroptosis is a proinflammatory programmed cell death that is related to several diseases. Thus, the purpose of this study was to examine whether pretreatment with octreotide (somatostatin analogue, OCT) at different doses or OCT at 75μg/kg combined with melatonin (N-acetyl-5-methoxytryptamine, MLT) can alleviate HIR injury via targeting NLRP3 inflammasome-induced pyroptosis in a TLR4/MyD88/NF-κB dependent manner.

METHODS

Rats were randomized into sham, HIR, OCT (50, 75, and 100 µg/kg), MLT, and MLT + OCT75 groups. Ischemia was induced via occlusion of the portal triad for 30 min followed by 24 h reperfusion.

RESULTS

OCT pretreatment at doses (50 or 75 μg/kg), MLT alone, and MLT + OCT75 significantly ameliorated the biochemical with histopathological changes, oxidative stress, inflammation, apoptosis, then augmented anti-oxidant and anti-apoptotic markers through downregulation of HMGB1, TLR4, MyD88, TRAF-6, p-IκBα (S32), p-NF-κBp65 (S536), NLRP3, ASC, caspase-1(p20), and GSDMD-N expressions compared with HIR group.

CONCLUSION

OCT at doses (50 or 75 µg/kg) showed for the first time a hepatoprotective effect against HIR injury via inhibiting TLR4-NLRP3-mediated pyroptosis in rats. As well, OCT75 was more effective than OCT50 or MLT alone, and its effect was not enhanced after the addition of MLT, through downregulation of TLR4/MyD88/NF-κB/NLRP3 inflammasome pathway.

Quantitative evaluation of dexamethasone treatment effects in renal ischemia-reperfusion injury using contrast enhanced ultrasonography in rats

BACKGROUND

Renal ischemia-reperfusion (I/R) injury often occurs in various clinical events, and its incidence and mortality have been increasing.

OBJECTIVE

To investigate the value of contrast enhanced ultrasonography (CEUS) in the monitoring of dexamethasone in the improvement of renal I/R injury in rats.

METHODS

Eighteen healthy male Sprague-Dawley rats were randomly divided into sham-operated, I/R, and I/R surgery plus dexamethasone treatment (Dexa) groups. In the I/R group 45-minute renal ischemia with 24 h reperfusion period was monitored. Time-intensity curve (TIC)-derived parameters, which included peak value, time to peak (TP), area under the curve (AUC), and mean transit time (MTT) were compared to the blood creatinine, urea, Caspase-1, and NLRP3 levels.

RESULTS

The I/R group showed an increased peak value, prolonged TP and MTT, and greater AUC (P < 0.05). The Dexa group showed shorter TP and MTT, and smaller AUC (P < 0.05). Results show that the associations between (i) TP, AUC, and MTT and (ii) creatinine, urea, Caspase-1, and NLRP3 levels were significant (P < 0.05).

CONCLUSION

Dexamethasone can alleviate renal I/R injury in rats, which may be related to the inhibition of NLRP3 and caspase-1. CEUS can quantitatively measure this change, in which the changes in TP, AUC and MMT values have considerable reference values.

Octreotide alleviates pancreatic damage caused by paraquat in rats by reducing inflammatory responses and oxidative stress

This study explores the efficacy and mechanism by which octreotide (OCT) alleviates paraquat (PQ)-induced pancreatic injury. Twenty-four adult male rats were randomly divided into three groups: the normal control (NC), PQ poisoning, and OCT treatment groups. The PQ-induced pancreatic injury rat model was established by administering PQ (120 mg/kg). Treatment group rats received OCT (8 μg/kg body weight) every 8 h by subcutaneous injection, 1 h after PQ administration. Rats were euthanized 24 h after PQ injection. Serum amylase, lipase, tumor necrosis factor-α, and interleukin-6 levels were markedly increased in the PQ group versus the NC group. In pancreatic tissue, PQ poisoning drastically induced necrosis and increased inflammatory cytokine and oxidative stress marker levels. Compared with the PQ group, OCT reduced pancreatic damage and histological scores, serum amylase, lipase, and inflammatory cytokine levels, as well as oxidative stress. OCT demonstrates protective effects against PQ-induced pancreatic damage through anti-inflammatory and antioxidant actions.

Nobiletin alleviates ischemia/reperfusion injury in the kidney by activating PI3K/AKT pathway

Recent studies have demonstrated that nobiletin (NOB) displays anti-oxidative and anti-apoptotic efficacies against multiple pathological insults. However, the potential effects of NOB on the injury caused by ischemia and reperfusion (I/R) in the kidney remain undetermined. In the present study, I/R injury was elicited by right kidney removal and left renal pedicel clamping for 45 min, followed by reperfusion for 24 h. NOB was added at the start of reperfusion. Histological examination, detection of biomarkers in plasma, and measurement of apoptosis induced by endoplasmic reticulum stress (ERS) were used to evaluate renal injury. Additionally, the PI3K/AKT inhibitor LY294002 was also used in mechanistic experiments. NOB pre-treatment significantly reduced renal damage caused by I/R injury, as indicated by decreased serum levels of creatine, blood urea nitrogen and tubular injury scores. Furthermore, NOB inhibited elevated ERS-associated apoptosis, as evidenced by reduced apoptotic rates and ERS-related signaling molecules (such as, C/EBP homologous protein, caspase-12 and glucose-regulated protein of 78 kDa). NOB increased phosphorylation of proteins in the PI3K/AKT pathway. The inhibition of PI3K/AKT signaling with pharmacological inhibitors could reverse the beneficial effects of NOB during renal I/R insult. In conclusion, NOB pre-treatment may alleviate I/R injury in the kidney by inhibiting reactive oxygen species production and ERS-induced apoptosis, partly through the PI3K/AKT signaling pathway.

Octreotide and lanreotide decrease ovarian ischemia-reperfusion injury in rats by improving oxidative and nitrosative stress

AIM

To investigate the protective effect of octreotide and lanreotide on ovarian damage in experimental ovarian ischemia-reperfusion injury.

METHODS

Fifty-six rats were separated into seven groups; group 1: sham group, group 2: surgical control group with 3-h torsion and detorsion, group 3: 0.02 mg/kg s.c. octreotide 30 min before 3-h torsion, group 4; octreotide just after detorsion for 7 days, group 5: octreotide 30 min before torsion and just after detorsion for 7 days, group 6: single time 20 mg/kg s.c. lanreotide before torsion, group 7: single time lanreotide just after detorsion.

RESULTS

All histopathological scores except congestion were significantly lower in group 1 than other groups. In addition, hemorrhage (group 2 vs 4: P < 0.05), degeneration (group 2 vs 4: P < 0.05, group 2 vs 5: P < 0.01 and group 2 vs 6: P < 0.05) and total damage score (group 2 vs 4: P < 0.05, group 2 vs 5: P < 0.05, group 2 vs 6: P < 0.05 and group 2 vs 7: P < 0.05) were significantly lower than other groups. Moreover, ovarian tissue total oxidant status and oxidative stress index levels were significantly decreased in groups 5 (both P < 0.05) and 7 (both P < 0.05) when compared to group 2. Furthermore, tissue levels of peroxynitrite were significantly higher in group 2 than groups 1, 3 and 5 (all P < 0.05).

CONCLUSIONS

Octreotide and lanreotide have a protective role against ischemia-reperfusion damage in rat torsion detorsion model by improving histopathological and biochemical findings including tissue levels of total oxidant status, oxidative stress index and peroxynitrite.

Isoquercitrin Attenuates Renal Ischemia/Reperfusion Injury Through Antioxidation, Anti-inflammation, and Antiapoptosis in Mice

Renal ischemia-reperfusion injury (RIRI) occurs after several surgical procedures such as kidney transplantation and partial nephrectomy. Isoquercitrin (IQ) exhibited protective effects in cerebral ischemia-reperfusion injury. In the present study, we aimed to evaluate the effects of IQ on the prevention of RIRI. The mouse model of RIRI was induced by 30-minute clamping of the left renal pedicle after excising of the right kidney, followed by 24-hour reperfusion. Thirty mice were randomly divided into the following 3 groups: sham operation, RIRI model group, and IQ pretreatment + RIRI. Serum creatinine and blood urea nitrogen (BUN) were used for evaluating renal function. Kidney cell apoptosis was measured by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining. Moreover, the pro-inflammatory cytokines (TNF-α, IL-6), the oxidative stress associated factors (malondialdehyde, superoxide dismutase), and the apoptotic factors (Bcl-2, Bax) were assessed. After RIRI, BUN, creatinine, TNF-α, IL-6, malondialdehyde, and Bax were significantly increased, and levels of superoxide dismutase and Bcl-2/Bax ratio and Bcl-2 expression were decreased markedly. As expect, IQ reversed these changes. These data indicate that IQ plays a protective role during RIRI, which may be partially mediated through the actions of antioxidation, anti-inflammation, and antiapoptosis.