[The correlations between plasma TNF-alpha, NO, NOS levels and brain lateralization in mice]

The brain modulates the immune system in an asymmetrical way, as shown by the association between paw preference and immune response in the mice. The purpose of the present work was to study the relationship between plasma tumor necrosis factor-alpha (TNF-alpha), nitric oxide (NO) and nitric oxide synthase (NOS) and brain lateralization. In the study, paw preference test was used to select right-pawed, left-pawed and ambidextrous mice. Mice were classified as the right-pawed if the right paw entry (RPE) score was equal to or greater than 30 (30-50), as the left-pawed if the score was equal to or less than 20 (0-20), and as the ambidextrous if the score was between 21 and 29. One week after the paw preference testing, the animals were injected intraperitoneally with either sterilized 0.9% saline or lipopolysaccharide (LPS) (5 microg/0.5 ml NS) and were killed 2 h later. Plasma was collected from each mouse. The level of plasma TNF-alpha was measured with ELISA kits provided by ENDOGEN. NO and NOS levels of plasma were detected with kits from Juli Biotechnology Company. The results showed that (1) in the normal mice, ambidextrous mice had higher NO levels compared with left-pawed mice (P<0.05). After the injection of LPS, plasma level of TNF-alpha was lower in left-pawed mice compared with those of the right-pawed and ambidextrous mice; plasma level of NO was higher in ambidextrous mice compared with those of the right- (P<0.01) and left-pawed (P<0.05) ones, and there was no significant difference in the plasma levels of NOS among ambidextrous, right- and left-pawed mice. (2) Immune parameters were correlated with the RPE scores. The shape of the curve describing this relation was similar to a parabola. In general, the levels of TNF-alpha, NO, NOS rose along with the increase of RPE if the scores were in the score range of left-pawed mice.After that, they reached a peak if the scores were in the score range of ambidextrous mice. Then they declined along with the increase of RPE if the scores were in the score range of right-pawed mice. In conclusion, plasma levels of TNF-alpha, NO and NOS were associated with brain lateralization, suggesting that the activities of Mo/Mphi were influenced by brain lateralization, and that the immune parameters were correlated with the RPE scores.