The brain clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus receives direct retinal input, thereby providing the entire body with an internal representation of external solar time. The pathways by...
Cytokines and chemokines play important roles in inflammation and repair following brain injury. M1 microglia are pro-inflammatory which produce cytokines and lead to neural injury;in contrast, M2 microglia are anti-i...
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Cytokines and chemokines play important roles in inflammation and repair following brain injury. M1 microglia are pro-inflammatory which produce cytokines and lead to neural injury;in contrast, M2 microglia are anti-inflammatory, release neurotrophic factors, and promote neural repair processes. Chemokine CCL5, increased after TBI, shows a neuroprotective function by reducing oxidative stress. CCL5 may contribute to the balance between oxidative stress and immune responses after brain injury. Herein, we investigated the role of CCL5 in microglial polarization after mild traumatic brain injury, focusing on the cerebral cortex.C57BL/6 and CCL5 knockout (CCL5-KO) mice were given a mild traumatic brain injury (TBI) using weight-drop. Neurological parameters such as motor and sensory functions were analyzed by mNSS score, accelerating rotarod, beam walking, and adhesive removal tests. Oxidative stress and neuron damage were measured by NAdph oxidase activity, hypoxyloprobe staining and FJC. Performance of motor and sensory functions in both WT and CCL5-KO mice were impaired after brain injury which recovered after 7 days-post-injury (dpi) in the WT group but only after 14 days in the CCL5-KO mouse group. RT-qPCR analysis revealed that pro-inflammation cytokines - IL-1β, TNF-α, and IL-6 were higher in CCL5-KO mice compared to WT mice at 4 and 14 dpi. In contrast, M2-like microglia markers - IL-10 and Agr-1 were increased in WT mouse cortical tissue at 4 dpi. Oxidative stress increased both M1 and M2- related cytokine expression in BV2 cells treated with H 2 O 2;CCL5 treatment increased M2- but suppressed M1- related cytokine gene activation. Intranasal delivery of CCL5 reduced neuronal oxidative stress, increased IL-10 expression and improved motor and sensory functions in CCL5-KO mice after brain *** summary, CCL5, which alters immune responses and protects neurons from TBI damage, has an important function in regulating M2-like microglial polarization during post-
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