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Since the outbreak of COVID‑19, severe acute respiratory syndrome coronavirus 2 genome is still mutating, forming a variety of variants with strong transmission capacity, causing the spread of the epidemic worldwide, posing a serious threat to people's physical and mental health, and posing a major challenge to global public health. Omicron remains the main variant in several outbreaks worldwide, accounting for about 99% of the global genetic sequence. Recently, the World Health Organization announced that the subvariant of Omicron BA.5 has been found in more than 100 countries and regions around the world, causing the global epidemic rebound. However, there are few studies on the subvariant BA.5. This article reviews the latest research progress in epidemiology, infectivity, pathogenicity, vaccine and monoclonal antibody protection against Omicron subvariant BA.5, in order to provide reference for scientific prevention and control of Omicron subvariant BA.5. [ABSTRACT FROM AUTHOR]

Objective: To observe the effect of moxibustion preconditioning on learning-memory ability, Toll like receptor 4(TLR4)/nuclear factor-kappa B(NF-κB) signal pathway related proteins and microglia in rats with Alzheimer's disease (AD), so as to explore its possible mechanisms underlying improvement of AD., Methods: Male SD rats were randomly divided into normal, sham operation, AD model and pre-moxibustion groups, with 9 rats in each group. Moxibustion was applied to "Baihui"(GV20), "Shenshu"(BL23) and "Zusanli"(ST36) for 15 min, once daily, 6 days as a course of treatment for 3 courses. At the end of moxibustion, the AD model was established by injection of Aβ 25-35 aggregation solution into the bilateral hippocampus. The sham operation group was only injected with the same amount of 0.9% Nacl solution. The spatial learning-memory ability of rats was detected by Morris water maze test, the ultrastructure of hippocampal neurons was observed by transmission electron microscope (TEM). The histopathological changes of hippocampus tissue were observed by HE staining, and the protein expression levels of TLR4 and NF-κB p65 in the hippocampus detected by Western blot, and the positive expressions of Iba-1, CD80 and CD206 in the hippocampal CA1 region were detected by immunofluorescence labeling. The contents of inflammatory factors IL-1β, TNF-α and IL-10 in the hippocampus were measured by ELISA., Results: Compared with the sham operation group, the escape latency was significantly increased ( P <0.01), and the number of platform quadrant crossing times was decreased ( P <0.01) in the model group. In comparison with the model group, the increased escape latency and the decreased platform quadrant crossing times were reversed in the pre-moxibustion group ( P <0.01). TEM and light microscope observation showed loose arrangement of cells, enlarged cell space, degeneration, swelling and deformation of hippocampal neurons, rupture of membranes of a large number of cells, reduction of mitochondria, dilation of endoplasmic reticulum, and matrix vacuoles, uneven distribution of organelles and cytoplasm, and being difficult in distinguishing the nuclear cytoplasm in the model group, which was relatively milder in the pre-moxibustion group. The expression levels of hippocampal NF-κB p65 and TLR4, the mean immunofluorescence density of Iba-1 and CD80, as well as the contents of IL-1β and TNF-α in hippocampal CA1 region were significantly increased in the model group than those in the sham operation group ( P <0.01), and obviously decreased in the pre-moxibustion group than those in the model group ( P <0.05, P <0.01). Whereas the expression of CD206 and the content of IL-10 were evidently decreased in the model group than those in the sham operation group ( P <0.01), and strikingly increased in the pre-moxibustion group than those in the model group ( P <0.01). No significant differences were found between the sham operation group and the normal group in all the indexes mention above ( P >0.05)., Conclusion: Pre-moxibustion at GV20, BL23 and ST36 can improve learning-memory ability in AD rats, which may be associated with its functions in promoting the polarization of microglia from M1 to M2 and reducing the neuroinflammatory response by way of TLR4/NF-κB signaling pathway.