Effects of melatonin on the serum levels of pro-inflammatory cytokines and tissue injury after renal ischemia reperfusion in rats

Protective Effect of Melatonin for Renal Ischemia-Reperfusion Injury: A Systematic Review and Meta-Analysis

Background: Renal ischemia-reperfusion (I/R) injury is one of the major causes related to acute kidney damage. Melatonin has been shown as a powerful antioxidant, with many animal experiments have been designed to evaluate the therapeutic effect of it to renal I/R injury.

Objectives: This systematic review aimed to assess the therapeutic effect of melatonin for renal I/R injury in animal models.

Methods and Results: The PubMed, Web of Science, Embase, and Science Direct were searched for animal experiments applying melatonin to treat renal I/R injury to February 2021. Thirty-one studies were included. The pooled analysis showed a greater reduction of blood urea nitrogen (BUN) (21 studies, weighted mean difference (WMD) = −30.00 [−42.09 to −17.91], p < 0.00001), and serum creatinine (SCr) (20 studies, WMD = −0.91 [−1.17 to −0.66], p < 0.00001) treated with melatonin. Subgroup analysis suggested that multiple administration could reduce the BUN compared with control. Malondialdehyde and myeloperoxidase were significantly reduced, meanwhile, melatonin significantly improved the activity of glutathione, as well as superoxide dismutase. The possible mechanism for melatonin to treat renal I/R injury is inhibiting endoplasmic reticulum stress, apoptosis, inflammation, autophagy, and fibrillation in AKI to chronic kidney disease.

Conclusions: From the available data of small animal studies, this systematic review demonstrated that melatonin could improve renal function and antioxidative effects to cure renal I/R injury through, then multiple administration of melatonin might be more appropriate. Nonetheless, extensive basic experiments are need to study the mechanism of melatonin, then well-designed randomized controlled trials to explore the protective effect of melatonin.

Dok3 is involved in cisplatin-induced acute kidney injury via regulation of inflammation and apoptosis

Cisplatin-induced acute kidney injury (AKI) is associated with high morbidity and mortality worldwide, but the underlying mechanisms are not fully understood. Downstream-of-kinase 3 (Dok3), a member of the Dok family of adaptor proteins plays a critical role in inflammatory response and immune regulation; however, the role of Dok3 in cisplatin-induced AKI remains unclear. This study explored the effect and potential molecular mechanisms of Dok3 in cisplatin-induced AKI using Dok3 knockout (Dok3-/-) and control mice (129S) with or without administration of a single intraperitoneal injection of cisplatin. Apoptosis was assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, lactate dehydrogenase (LDH) release, and Hoechst staining. Inflammatory factors were measured using ELISA kits. Protein and gene expression levels were measured by western blot analysis and real-time PCR, respectively. The results showed that Dok3 was expressed in renal tubular epithelial cells. Dok3 expression was decreased in kidneys of mice treated with cisplatin and cisplatin-treated HK2 cells. Dok3-/- mice showed lower creatinine levels and NGAL expression, and increased survival rates compared to 129S mice. Cisplatin-induced production of TNF-α and IL-6, and renal tubular cell apoptosis was attenuated in Dok3-/- mice. In vitro experiments demonstrated that HK2 cells overexpressing Dok3 exhibited exacerbated cisplatin-induced apoptosis and production of TNF-α and IL-6. These findings demonstrate that Dok3 regulates cisplatin-induced AKI by regulating apoptosis and inflammation.

Ameliorative effect of umbelliferone in remote organ injury induced by renal ischemia-reperfusion in rats

We evaluated the ameliorative role of umbelliferone in kidney, heart, and lung damage induced by renal ischemia/reperfusion (I/R) injury in rats. Umbelliferone was given orally to rats 60 min before ischemia. Ischemia was induced for 50 min and then reperfusion for 3 hr. The antioxidant enzymes, myeloperoxidase (MPO) activity, malondialdehyde (MDA) content, and cytokine levels in the kidney, heart, and lung were measured by ELISA. Moreover, histopathological changes were monitored. Renal I/R-induced oxidative stress in the organs by decreasing antioxidant enzymes. However, umbelliferone pretreatment enhanced superoxide dismutase (SOD) and glutathione (GSH), levels, reduced MDA and MPO levels. Renal I/R increased in tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) levels, and histopathological changes but these effects were inhibited with umbelliferone pretreatment. Furthermore, umbelliferone increased in nitric oxide synthase (eNOS) level under ischemia conditions. Our results indicated that pretreatment of umbelliferone-ameliorated damages in remote organ induced by renal I/R through suppressing oxidative stress and modulating inflammatory responses. PRACTICAL APPLICATIONS: kidney, heart, and lung damages induced by renal I/R in rats was alleviated by umbelliferone. The oral treatment of umbelliferone markedly reversed the oxidative stress, inflammation, and histopathological changes by increasing in the levels of SOD, GSH, and eNOS, decreasing in the levels of MDA, MPO, TNF-α, and IL-6 in distant organ injury induced by renal I/R. This study firstly revealed that umbelliferone has potent antioxidant and anti-inflammatory activity in the remote organ damages caused by renal I/R. Consequently, umbelliferone may be an alternative therapeutic agent for treating renal I/R-induced damages.

The immune-sleep crosstalk in inflammatory bowel disease

Sleep disorders are progressively common and sometimes are associated with aberrant regulation of the adaptive and innate immune responses. Sleep interruption can increase the inflammatory burden by enhancing the pro-inflammatory cytokines particularly in patients with chronic diseases such as inflammatory bowel disease (IBD). IBD is a chronic inflammatory disease characterized by immune dysregulation, dysbiosis of gut microbiome, and poor-quality life. Therefore, this review highlights the crosstalk between sleep and immune responses during the progression of IBD.

Sleep Time Duration Does Not Affect Oral Inflammation and Periodontal Health Status in Night-Shift Workers: A Cross-Sectional Study

BACKGROUND

Night-shift workers experience circadian rhythm disruption, changes in sleep time duration, and effects on their eating habits. All these factors may be related to the release of inflammatory mediators and may affect oral inflammation and periodontal health status. The objective of this study was to analyze the effects of sleep time duration on oral inflammation and periodontal health status in night-shift workers and non-night-shift workers.

METHODS

This study involved two groups with 27 participants each: one group of night-shift workers and one group of non-night-shift workers. Examination of depth of pocket and bleeding on probing (BOP) was conducted with a periodontal probe. Non-stimulating saliva samples were collected to analyze the levels of melatonin, malondialdehyde (MDA), and tumor necrosis factor α (TNF-α) using ELISA. Comparisons for each parameter were performed using independent t-tests, and the relationships between duration of sleep and depth of pocket, BOP, salivary melatonin, MDA, and TNF-α were calculated using linear regression.

RESULTS

The night-shift worker group had a short sleep time duration (p = 0.000). The salivary melatonin level of the night-shift workers was lower than that of the non-night-shift workers (p = 0.000). MDA, depth of pocket, and BOP were higher in the night-shift workers (p = 0.000). Only salivary melatonin showed a correlation with sleep time duration in the night-shift worker group (p < 0.05). Neither subject group showed an effect of sleep time duration on depth of pocket, BOP, salivary melatonin, MDA, or TNF-α (p > 0.05).

CONCLUSION

Night-shift workers showed higher rates of oral inflammation and periodontal health status, but there was no relationship between these factors and sleep time duration.

Melatonin therapy protects against renal injury before and after release of bilateral ureteral obstruction in rats

AIM

Blockage of the urinary tract is often connected with renal function impediment, including reductions in glomerular filtration rate (GFR) and the power to control sodium as well as water elimination through urination. Melatonin, known to be the primary product of the pineal gland, prevents renal damage caused by ischemic reperfusion. However, the effects of melatonin on urinary obstruction, as well as release of obstruction induced kidney injury are still largely unknown. The aim of present study was to investigate the effect of melatonin on mediating protection against renal injury triggered from either bilateral ureteral obstruction (BUO) or BUO release (BUO-R).

MAIN METHODS

Adult male Sprague-Dawley rats (n = 60) were clustered into six treatment groups: sham treated-1; BUO-non-treated (24 h BUO only); BUO + melatonin; sham treated-2; BUO-48hR (24 h of BUO and then release for 2 days); and BUO-48hR + melatonin. Kidney tissues, blood and urine samples were obtained for further assessment.

KEY FINDINGS

It was found that melatonin treatment remarkably promoted the recovery of the handling capacity of urinary excretion of water as well as sodium in BUO and BUO-48hR models. Melatonin treatment partially inhibited inflammatory cytokine expression and the downregulation of aquaporin (AQPs, AQP-1, -2 and -3) expression in these two models. Moreover, the cytoarchitecture of BUO rats exposed to melatonin was well preserved.

SIGNIFICANCE

Melatonin treatment potently prevents BUO or BUO-R induced renal injury, which may be partially attributed to restoring the expression of AQPs and inhibition of inflammatory response, as well as preserving renal ultrastructural integrity.

Melatonin attenuates acute kidney ischemia/reperfusion injury in diabetic rats by activation of the SIRT1/Nrf2/HO-1 signaling pathway

Background and aims: Diabetic kidney is more sensitive to ischemia/reperfusion (I/R) injury, which is associated with increased oxidative stress and impaired nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling. Melatonin, a hormone that is secreted with the rhythm of the light/dark cycle, has antioxidative effects in reducing acute kidney injury (AKI). However, the molecular mechanism of melatonin protection against kidney I/R injury in the state of diabetes is still unknown. In the present study, we hypothesized that melatonin attenuates renal I/R injury in diabetes by activating silent information regulator 2 associated protein 1 (SIRT1) expression and Nrf2/HO-1 signaling. Methods: Control or streptozotocin (STZ)-induced Type 1 diabetic rats were treated with or without melatonin for 4 weeks. Renal I/R injury was achieved by clamping both left and right renal pedicles for 30 min followed by reperfusion for 48 h. Results: Diabetic rats that were treated with melatonin undergoing I/R injury prevented renal injury from I/R, in aspects of the histopathological score, cell apoptosis, and oxidative stress in kidney, accompanied with decreased expressions of SIRT1, Nrf2, and HO-1 as compared with those in control rats. All these alterations were attenuated or prevented by melatonin treatment; but these beneficial effects of melatonin were abolished by selective inhibition of SIRT1 with EX527. Conclusion: These findings suggest melatonin could attenuate renal I/R injury in diabetes, possibly through improving SIRT1/Nrf2/HO-1 signaling.

The multiple functions of melatonin in regenerative medicine

Melatonin research has been experiencing hyper growth in the last two decades; this relates to its numerous physiological functions including anti-inflammation, oncostasis, circadian and endocrine rhythm regulation, and its potent antioxidant activity. Recently, a large number of studies have focused on the role of melatonin in the regeneration of cells or tissues after their partial loss. In this review, we discuss the recent findings on the molecular involvement of melatonin in the regeneration of various tissues including the nervous system, liver, bone, kidney, bladder, skin, and muscle, among others.

Berberine protects HK-2 cells from hypoxia/reoxygenation induced apoptosis via inhibiting SPHK1 expression

Renal ischemia reperfusion injury (RIRI) refers to the irreversible damage for renal function when blood perfusion is recovered after ischemia for an extended period, which is common in clinical surgeries and has been regarded as a major risk for acute renal failures (ARF) that is accompanied with unimaginably high morbidity and mortality. Hypoxia during ischemia followed by reoxygenation via reperfusion serves as a major event contributing to cell apoptosis, which has been widely accepted as the vital pathogenesis in RIRI. Preventing apoptosis in renal tubular epithelial cell has been considered as effective method for blocking RIRI. In this paper, we established a hypoxia/reoxygenation (H/R) injury model in human proximal tubular epithelial HK-2 cells. Here, we found increased SPHK1 levels in H/R injured HK-2 cells, which could be significantly down regulated after berberine treatment. Berberine has been reported to exert a protective effect on H/R-induced apoptosis of HK-2 cells. So, in our present study, we planned to investigate whether SPHK1 participated in the anti-apoptosis process of berberine in H/R injured HK-2 cells. Our study confirmed the protective effect of berberine against H/R-induced apoptosis in HK-2 cells through promoting cells viability, inhibiting cells apoptosis, and down-regulating p-P38, caspase-3, caspase-9 as well as SPHK1, while up regulating the ratio of Bcl-2/Bax. However, SPHK1 overexpression in HK-2 cells induced severe apoptosis, which can be significantly ameliorated with additional berberine treatment. We concluded that berberine could remarkably prevent H/R-induced apoptosis in HK-2 cells through down-regulating SPHK1 expression levels, and the mechanisms included the suppression of p38 MAPK activation and mitochondrial stress pathways.

Rutaecarpine alleviates renal ischemia reperfusion injury in rats by suppressing the JNK/p38 MAPK signaling pathway and interfering with the oxidative stress response

In the present study, the protective effect and the potential underlying mechanism of rutaecarpine (Ru) on renal ischemia reperfusion injury (IRI) in rats were investigated. A renal ischemia reperfusion mouse model was established. Ru at 30, 60 mg/kg administered intraperitoneally prior to reperfusion led to attenuated renal injury. The results demonstrated that Ru treatment significantly reduced the content of serum creatinine, urea nitrogen and neutrophil gelatinase‑associated lipocalin in rats with renal IRI. In addition, Ru treatment improved the degree of renal proximal tubular necrosis, decreased the content of inflammatory cytokines in reperfused renal tissue and increased serum superoxide dismutase levels to protect the kidney. The associated underlying mechanism may involve the inhibition of p38 kinase phosphorylation and c‑Jun N‑terminal kinase, anti‑lipid peroxidation, elimination of free radicals, and a reduction in the degree of apoptotic damage and oxidative stress injury induced by renal IRI. Therefore, Ru may be a suitable compound for the prevention and treatment of renal IRI.

Effects of Lycopene Alone or Combined with Melatonin on Methotrexate-Induced Nephrotoxicity in Rats

Methotrexate (Mtx), used for its anticancer and immunsuppresive properties, is known to be a nephrotoxic agent. We aimed to investigate the effects of lycopene (Lyc) alone or combined with melatonin (Mel) on Mtx- induced nephrotoxicity since both of these agents have antioxidant and anti-inflammatory effects. Nephrotoxicity was induced by intraperitoneal administration of methotrexate at a dose of 20 mg/kg. Treatment both with Lyc alone and Lyc combined with Mel provided significant reduction in tumor necrosis factor-alpha, interleukin 1-beta and ceruloplasmin levels in Mtx administered rats. Hovewer, Lyc combined with Mel provided a significant reduction also in NO levels. Hstopathological examination showed that there was an obvious improvement in the degenerative changes compared to Mtx administrated group with the Lyc combined Mel group giving best protection. In conclusion Lyc alone and combined with Mel provided significant improvement against renal damage caused by Mtx, preseumably via antioxidant and anti-inflammatory activities.