Topological Reorganizations in the Rat Brain-Isolated Mitochondria after 72 Hours of Paradoxical Sleep Deprivation Revealed by Electron Cryo-Tomography

Sleep deprivation has profound influence on several aspects of health and disease. Mitochondria dysfunction has been implicated to play an essential role in the neuronal cellular damage induced by sleep deprivation, but little is known about how neuronal mitochondrial ultrastructure is affected under sleep deprivation. In this report, we utilized electron cryo-tomography to reconstruct the three-dimensional (3D) mitochondrial structure and extracted morphometric parameters to quantitatively characterize its reorganizations. Isolated mitochondria from the hippocampus and cerebral cortex of adult male Sprague-Dawley rats after 72 h of paradoxical sleep deprivation (PSD) were reconstructed and analyzed. Statistical analysis of six morphometric parameters specific to the mitochondrial inner membrane topology revealed identical pattern of changes in both the hippocampus and cerebral cortex but with higher significance levels in the hippocampus. The structural differences were indistinguishable by conventional phenotypic methods based on two-dimensional electron microscopy images or 3D electron tomography reconstructions. Furthermore, to correlate structure alterations with mitochondrial functions, high-resolution respirometry was employed to investigate the effects of PSD on mitochondrial respiration, which showed that PSD significantly suppressed the mitochondrial respiratory capacity of the hippocampus, while the isolated mitochondria from the cerebral cortex were less affected. These results demonstrate the capability of the morphometric parameters for quantifying complex structural reorganizations and suggest a correlation between PSD and inner membrane architecture/respiratory functions of the brain mitochondria with variable effects in different brain regions.

Paradoxical sleep deprivation induces oxidative stress in the submandibular glands of Wistar rats

Objectives Paradoxical sleep deprivation has been associated with impaired salivary secretion in rats. However, the mechanism that underlies this is not known. Therefore, this study assessed salivary and serum oxidative stress levels following paradoxical sleep deprivation in rats. Methods Twenty-one male Wistar rats randomly divided into three groups of seven rats each as; Control (C); partial sleep-deprived (PSD); and total sleep-deprived (TSD) were used. Malondialdehyde (MDA) concentration, Superoxide dismutase (SOD), and catalase activities were evaluated in saliva, serum, and submandibular glands after seven days of sleep deprivation. Data were expressed as mean ± standard error of the mean and analyzed using one-way ANOVA, Tukey HSD post hoc, and Pearson’s correlation tests. Results Serum MDA levels were significantly higher in both the TSD and PSD groups compared to the control group whereas only the TSD group showed higher submandibular MDA levels compared to the PSD group and the control group. Submandibular SOD activity was significantly lower in both the TSD and PSD groups compared to the control group. Serum catalase activity was significantly lower in the TSD group only compared to the control group. Conclusions These results have demonstrated for the first time that paradoxical sleep deprivation was associated with changes in the oxidant/antioxidant defense system in the submandibular salivary glands of male Wistar rats which may contribute to impairment in salivary secretion.

SLEEP DEPRIVATION INTERFERES WITH JAK/STAT SIGNALING PATHWAY AND MYOGENESIS IN MASSETER MUSCLE OF RATS

jectives. This study evaluated the JAK/STAT signaling pathway and myogenesis on masseter muscle after sleep deprivation as well as to investigate the role of stress in this scenario. Subjetcts and Methods. A total of 18 male Wistar rats were distributed into the following groups: Control (CTRL; n=6): animals were not submitted to any procedures; Sleep Deprivation and Vehicle (PSD+V; n=6): animals were subjected to Paradoxical Sleep Deprivation for 96h and (PSD+MET; n=6): animals were subjected to Paradoxical Sleep Deprivation for 96h with administration of metyrapone. Paradoxal Sleep deprivation was performed by the Modified Multiple Platforms Method. Histopatological analysis, histomorphmetry and immunohistochemistry were performed. Results and Conclusion. The results showed the presence of inflammatory infiltrate in the PSD+V and PSD+MET groups and atrophy. Histomorphometry showed that Cellular Profile Area decreased while Cellular Density increased in both experimental groups. Expression of p-STAT 3, MyoD and MyoG increased in PSD+V group, while the PSD+MET group increased expression of IL-6 and p-STAT 3. Our results are consistent with notion that sleep deprivation induced inflammatory response and atrophy in masseter muscle of rats.