ABSTRACT
Objective To investigate the effect of environmental enrichment (EE) on lipopolysaccharide (LPS) induced cognitive dysfunction in mice. Methods A total of thirty six 3 weeks old Kunming mice experienced 8 weeks of EE or standard environment (SE) feeding. After 8 weeks, they were divided into three groups: standard environment+ normal saline (SE+NS) group, standard environment+lipopolysaccharide (SE+LPS) group, environmental enrichment+ lipopolysaccharide (EE+LPS) group. The open field test was used to measure the locomotive of mice, and the cognitive function was determined by novelty object recognition test. The expression of microglial marker ionized calcium binding adaptor molecule-1 (IBA-1) in hippocampus was determined by immunohistochemical staining. The expression of microglial activation marker CD68 and NOD-like receptor protein 3 (NLRP3) inflammasome related protein in the hippocampus was detected by Western blotting. Results In the open field test, there was no difference in the activity among the three groups. Compared with the SE + NS group, SE + LPS group showed decreased discrimination ratio in novelty object recognition task, with remarkably up-regulated expression of CD68 in the hippocampus (P< 0. 01) . In addition, SE+LPS group exhibited significantly enhanced expression of NLRP3, apoptosis associated speck-like protein (ASC), Caspase-1 and interleukin-1β(IL-1β) in the hippocampus compared with SE + NS group (P < 0. 05) . Compared with the SE + LPS group, EE+LPS group showed enhanced discrimination ratio in the object recognition task, with down-regulated expression of CD68, NLRP3, ASC, Caspase-1, IL-1β and IL-18 in the hippocampus (P < 0. 01) . Conclusion Environmental enrichment can alleviate LPS induced cognitive dysfunction, which might be attributed to the inhibiting of microglia and NLRP3 activation in the hippocampus.
ABSTRACT
Objective To detect the dynamic expression of insulin-like growth factor 2 (IGF2) in lateral geniculate body (LGB) during the critical period of visual development. Methods Three groups of Kunming mice of different ages were selected for testing, which were 3 weeks old, 5 weeks old and 7 weeks old, twelve in each group. The forepaw-reaching reflex test was used to detect whether the visual function of the mice was normal in each group. Immunohistochemical technique was used to detect the expression of IGF2 protein and its receptor in the lateral geniculate body of normal mice at week 3, 5 and 7 postnatal, and to analyze the expression of the protein of IGF2 and its receptor in each part of the lateral geniculate body. Results The expression of IGF2 protein in the dorsal lateral geniculate nucleus decreased significantly at week 5 postnatal and increased significantly at week 7 postnatal, and increased gradually over time at week 5 and week 7 postnatal in the ventral geniculate nucleus. The expression of IGF2 receptor protein in the dorsal lateral geniculate nucleus and ventral nucleus increased significantly at week 5 postnatal, and at week 7 postnatal, the expression of IGF2 receptor decreased to week 3 level in lateral geniculate body of mice. Conclusion The expression of IGF2 and its receptor in lateral geniculate body of mice during critical period of visual development changed dynamically, and the expression patterns of IGF2 and its receptor in different parts of LGB were not completely consistent. The expression of IGF2 and its receptors may be related to the plasticity of visual development in mice.