| Brain lateralization could affect the immune system. Some immune parameters were different in right-pawed, left-pawed and ambidextrous mice. In the neuroendocrine-immune network, hypothalamic-pituitary-adrenal(HPA) axis was an important pathway between the brain and the immune system. Cytokine IL-lβ, IL-6 in hippocampus and hypothalamus had modulation effects on the HPA axis. The purposes of the present work were to study the interactions between hippocampal and hypothalamic cytokines, HPA axis and brain lateralization, and to analyse the relationship between these cytokines and brain lateralization in the modulation of HPA axis. Methods:Balb/c female mice (4-week-old), by using paw preference test,the right-pawed, left-pawed and ambidextrous mouse model was established. Mice were classified as right-pawed if the RPE(right paw entry) score was equal to or greater than 30,as left-pawed if the RPE score was equal to or less than 20, and ambidextrous if the score was between 21 and 29. Lipopolysaccharide (LPS, Escherichia coli, 026:B6, Sigma), 10 g/ml was dissolved in sterile saline, 0.5mL/mouse was injectedintraperitoneally;each mouse in control group was received an equivalent injection of 0.5mL sterile saline. The animals were killed by decapitation 2h after the injection of LPS. The whole left, right hippocampi and hypothalami were rapidly removed and separated on ice, then they were quickly frozen on -80?C until the time of being homogenized. Each hippocampus was weighed and homogenized in 0.01 M phosphate-buffered saline (pH 7.4, 4, 1:10, weight/volume). The homogenate was centrifuged (10,000 g , 15min, 4), and the supernatant was stored at -80?C. The IL-16 and IL-6 levels of tissue homogenates were measured using enzyme-linked immunosorbent assay(ELISA) kits purchased from Pharmingen. Some of the animals were used to measure IL-1 P IL-6 mRNAs in the hippocampus and hypothalamus. Animals were killed by decapitation 2h after the injection of LPS, then the whole left and right hippocampus and hypothalamus were rapidly removed and separated on ice.IL-1 P-, IL-6 mRNAs in the hippocampus and hypothalamus of mice were investigated quantitatively by fluorogenic quantitative reverse transcription polymerase chain reaction(FQ-RT-PCR). Result:1 . In the physiological condition,no differences in IL-1 P contents were observed between bilateral hippocampi of right-pawed, left-pawed and ambidextrous mice.For the LPS treated mice: the IL-1 P level of bilateral hippocampi was increased, the IL-1 P level of right-pawed was higher than that of left-pawed (P<0.05)and ambidextrous mice(P<0.01). The IL-1 P mRNA expression after LPS treatment was higher in right-pawed mice than in left-pawed and ambidextrous mice(P<0.05).2. In saline treated mice, there were significantly differencesbeween the three groups:IL-6 level in hippocampus of right-pawed group was higher than that of left-pawed group ( P<0.01) , and IL-6 level of left-pawed group was higher than that of ambidextrous group ( P<0.001 ) .There were no significantly differences between bilateral hippocampi. In LPS treated mice, total IL-6 level of Balb/c mice had no change,but the IL-6 level in right hippocampus of right-pawed increased significantly compared with that in right hippocampus of left-pawed ( P<0.05 ) and ambidextrous mice. The IL-6 mRNA expression after LPS treatment was higher in right-hippocampus of right-pawed mice than in right-hippocampus of left-pawed and ambidextrous mice(P<0.05).3 . In the physiological condition,no differences in IL-1 P contents were observed between the hypothalami of right-pawed, and left-pawed mice. IL-1 P contents were higher than ambidextrous mice(P<0.05). For the LPS treated mice: the IL-1 P level of hypothalami had no change. The IL-1 P mRNA expression after LPS treatment was increased in Balb/c mice,but there was no difference between brain lateralized mice.4. In the physiological condition,no differences in... |
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