The Correlation Between Cytokine Production by Cerebral Cortical Glial Cells and Brain Lateralization in Mice

Abstract

Objectives. This study aims to explore the relationship among the levels of interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) produced by cortical glial cells, and identify any correlation between neuromodulation and brain lateralization. Material and Methods. Cortical glial cells from Balb/c neonatal mice were cultured in vitro and the effects of treating or not treating these cells from both hemispheres with lipopolysaccharide (LPS) (10µg/mL) for 24hours were tested. The levels of IL-1β, IL-6, and TNF-α in left and right cortical glial cell cultures and the time course of any changes were compared. Rusults. The production of IL-1β and TNF-α had no significant difference between right and left cortex in the untreated group within 24hours. IL-6 was significantly higher in the right than the left cortical glial cells. In the LPS-treated group, increased levels of IL-1β, TNF-α, and IL-6 were found, particularly for IL-6, and all were significantly increased in cortical glia cells from the right side. The time course shows that the expression of IL-1β in right cortex and IL-6 in both sides is time-dependent (p<0.05). Conclusion. Lipopolysaccharide increases cytokine production in both cerebral cortices, three cytokines have different expression time course within 72hours, but only IL-1β in right cortex and IL-6 releasing is time-dependent, and more so on the right side than the left in 24hours. We proposed the increased immunosuppressive activity of right cortex was due to the higher expression of IL-1β, TNF-α, and IL-6 in the right cortical glial cells, whereas there would be more immunoenhancement activity of the left cortex due to the lower levels of these three kinds of cytokines, this being a less pronounced effect than that on the right side. One of the reasons for the brain lateralization may be the different production of cytokines by the cortical glial cells on either side.