The Molecular And Cellular Bases Of Brain Lateralization Affecting Neuroimmunoendocrine

Background & Objective: Brain lateralization is a universal phenomenon and the two sides of the brain are differently involved in the modulation of inmune responses as demonstrated by lesional and behavioral approaches. In the physiological condition the right neocortex depresses immune functions, whereas the left neocortex enhances immune functions. With the paw preference in a food-reaching task as an index of lateralization, the relationship between lateralization and immune activities was demonstrated. Paw preference was associated with some immune parameters and previous studies also shew that the activities of hypothalamic-pituitary-adrenal (HPA)axis were influenced by lateralization. The purposes of the present work were to study the interactions between cerebral cortex cytokines, monocyte/macrophage (MaIM (1) ) ,astrocytes and brain lateralization,and to analyse the relationships between these immune parameters and brain lateralization in modulation of immune system. Methods: Paw preference test was used to select right-pawed, left- pawed and ambidextrous mice. Mouse was classified as right--pawed(RP) when the right paw entry (RPE) score was equal to or greater than 30(30- 50),left-pawed (LP) when the score was equal to or less than 20(0-20),and ambi-dextrous(L/R) when the score was between 21 and 29(21-29). One week after the paw preference testing, the animals were injected intraperitoneally with sterile 0.9% saline or LPS 5 ii g/0.Sml NS and were killed 2h later. The plasma was collected and neoeortex homogenates were prepared from the left and right cerebral cortices of each animal. TNF- Q levels of plasma,IL- 1 P and IL-6 contents of neocortex homogenate were measured with ELISA kits provided by ENDOGEN. Nitric Oxide (NO) levels of plasma and neocortex homogenate and NO synthase ~NOS) levels of plasma were detected with kits from Juli Biotechnology 4 駘fr~Y~ Company. The brains and hippocampi of another two groups of mice were taken out and were embeded in paraffin, 4 ii m thick sections were made coronally and were mounted on the slides. Immunohistochemical SABC method was performed on the paraffin sections of brains and hippocampus to detect the expression of glial fibrillary acidic protein(GFAP). Results: 1) IL-i ~ ,IL-6 and NO contents of neocortex homogenates: (ii) IL-i ~ ,IL-6 and NO contents in normal mice were all higher in right cortices compared with left cortices(P