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Background. General anesthesia in early childhood may affect all aspects of neurodevelopment, resulting in learning and behavior defects. Therefore, there is an urgent need to find safe anesthetics or put forward more comprehensive anesthesia schemes to solve the negative effects caused by existing anesthetics. The objective of this study is to explore the impact of dexmedetomidine (Dex) incorporated with low-dose propofol (PRO) on learning and memory ability and neural cells in developing rats. Methods. Eighty SD rats were randomly divided into 4 groups including the Sham group, Lipid group, L-PRO group, and Dex + L-PRO group. After treatment, the spatial learning and memory ability of rats in each group were assessed by the water maze test and the passive avoidance test. The damage of hippocampal tissues was assessed by Nissl staining; the apoptosis, the levels of inflammatory factors, and the level of oxidative stress were measured by Tunel staining, ELISA, and biochemical assays, respectively. Besides, qRT-PCR and Western Blot determined the expression of apoptosis-related proteins, neurotrophic factors, and MAPK signaling pathway-related proteins in the hippocampus. Results. Compared with the L-PRO group, the Dex + L-PRO group had better spatial learning and memory ability. Administration of Dex and L-PRO greatly alleviated neural cell damage in the hippocampus and decreased the levels of IL-6, IL-1β, and TNF-α. Besides, it significantly decreased the content of ROS and malondialdehyde (MDA), glutathione (GSH), when up-regulating the levels of IL-10, antioxidant superoxide dismutase (SOD) and BDNF, receptor tyrosine kinase B (TrkB), and neurotrophin-3 (NT-3) related to hearing function and significantly lower activity of MAPK signaling pathway. Conclusion. Dex combined with low-dose PRO can significantly inhibit inflammation, oxidative stress response, neuronal apoptosis, MAPK signaling pathway activity and promote the secretion of neurokines in hippocampus to reduce neural cell damage and avoid the learning and memory impairment caused by anesthetics in developing rats. [ABSTRACT FROM AUTHOR]

Objective. To compare the expressions of miRNAs (microRNAs) in serum exosomes and in hippocampus and to provide insights into the miRNA-mediated relationship between peripheral and central nervous systems in the presence of methamphetamine. Methods. Published results on conditioned place preference (CPP) in rats conditioned by methamphetamine were replicated. The expressions of miRNAs in serum exosomes and hippocampus were determined by gene-chip sequencing. We then predicted the potential target genes of selected, differentially expressed (DE) miRNAs and then carried out functional analysis of these target genes. We also verified our results by RT-qPCR. Results. Methamphetamine reward could greatly increase the activity time and distance in the intrinsically nonpreferred side of the behavioral apparatus compared with control rats (P<0.01). Rhynchophylline treatment significantly counteracted these changes (P<0.01). Methamphetamine-induced CPP upregulated 23 miRNAs (log2 fold change [FC] > 1, P<0.01) in serum exosomes, whereas rhynchophylline treatment could downregulate these miRNAs (log2 FC < −1, P<0.01). Analysis of hippocampal miRNAs profiles found 22 DE miRNAs (log2 FC > 1 or <−1, P<0.01). When methamphetamine induced CPP, 11 of those miRNAs were upregulated, whereas rhynchophylline treatment could downregulate these miRNAs. The other 11 miRNAs behaved in the opposite way. We selected six DE miRNAs from each of serum exosomes and hippocampus for target gene prediction and functional analysis. We found that, in both, the DE miRNAs and their target genes may be related to neuronal information transmission and synaptic transmission. Conclusions. Rhynchophylline blocked the alteration of behavior and the expression of some DE miRNAs induced by methamphetamine. The biological functions of these DE miRNAs target genes are correlated between serum exosomes and hippocampus. As to these biological processes and pathways which are involved in the development of addiction at multiple stages, we speculate that these DE miRNAs in serum exosomes and hippocampus are closely related to methamphetamine addiction. [ABSTRACT FROM AUTHOR]