Melatonin (Mel) is widely used to attenuate ischemia/reperfusion (I/R) injury in several organs. Nevertheless, the underlying mechanisms remain unclear. This study was conducted to explore the effect of Mel on endoplasmic reticulum (ER) stress, Akt and MAPK cascades after renal warm I/R. Eighteen Wistar rats were randomized into three groups: Sham, I/R, and Mel + I/R. The ischemia period was 60 min followed by 120 min of reperfusion. Mel (10 mg/kg) was administrated 30 min prior to ischemia. The creatinine clearance, MDA, LDH levels, and histopathological changes were evaluated. In addition, Western blot was performed to study ER stress and its downstream apoptosis as well as phosphorylation of Akt, GSK-3β, VDAC, ERK, and P38. Mel decreased cytolysis and lipid peroxidation and improved renal function and morphology compared to I/R group. Parallely, it significantly reduced the ER stress parameters including GRP 78, p-PERK, XBP 1, ATF 6, CHOP, and JNK. Simultaneously, p-Akt level was significantly enhanced and its target molecules GSK-3β and VDAC were inhibited. Furthermore, the ERK and P38 phosphorylation were evidently augmented after Mel administration in comparison to I/R group. In conclusion, Mel improves the recovery of renal function by decreasing ER stress and stimulating Akt pathway after renal I/R injury.

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We investigated the implication of AMP-activated protein kinase (AMPK) in melatonin-induced protection in a renal ischemia/reperfusion (I/R) model. Animals were divided into four groups: rats of the sham group were not subjected to renal I/R. Rats in the I/R group received the vehicle 30 min before renal ischemia for 1 h followed by reperfusion for 6 h. Rats in the Mel+I/R group received melatonin (10 mg/kg) 30 min before the onset of I/R. Rats in the Mel+I/R+araA group received araA (AMPK inhibitor, 100 µg/kg per min for 10 min) just before melatonin administration. The results showed that melatonin treatment induced a significant improvement in renal function, morphology, and antioxidant status, as well as Akt pathway activation. It also decreased cytolysis and endoplasmic reticulum stress. Inhibition of AMPK by araA administration completely abolished the effects of melatonin in regard to the above parameters except for Akt and some of its downstream target molecules. These results demonstrate that the effects of melatonin on renal I/R are, for the most part, linked to AMPK activation, with the exception of the Akt pathway, which seems to be independent of AMPK.

Purpose of the work: To assess the impact of fixed night shift on the vigilance of paramedical staff. Methods: The present study is an exhaustive cross-sectional survey which has been conducted at the University Hospital of Monastir, Tunisia, and it is about 92 care agents working permanently the night. The study of vigilance is based on Epworth scale and Super Lab program. Results: The average age was equal to 42.53 ± 9.45 years with a sex ratio of 1.72. Nurses accounted for 72%. The average score of alertness assessed with Epworth scale was equal to 14.5 ± 6. The use of the Super Lab software has objectified a tendency towards the increase in the average time of reaction of accomplishment of the simple task and the positive cueing task, which was evaluated while starting the shift, during the half time of the work and at the end of the shift. In addition, the average rate of errors evaluated at the beginning, half-time and at the end of the work has increased during 3 tests (simple task, positive and negative cueing tasks) without this difference being statistically significant. Conclusion: The alteration of vigilance with an ascent of the error rate among fixed night shift workers is a reality, which puts in question, not only the health of paramedical staff but also the care safety provided by these teams.