[Effects of hypergravity exposure after 30 days of simulated weightlessness on chemokine CCL20 and its receptor CCR6 in gingival tissue of rhesus macaque]

To study the effect of hypergravity exposure after 30 days of simulated weightlessness on the expression of chemokine CCL20 and its receptor CCR6 in gingival tissue of rhesus macaque.Twenty-three male rhesus monkeys were randomly divided into 4 groups, namely control group (A,n=3), weightlessness group (B,n=3), hypergravity group (C,n=3) and hypergravity exposure after 30 days of simulated weightlessness group (D, n=14). Group D was further divided into 4 subgroups according to the values of overload as: +11 Gx /270 s group (D1, n=3), +13 Gx /230 s group (D2,n=4), +15 Gx/200 s group (D3,n=4) and +13 Gx /230 s with 9 days of recovery group (D4, n=3). Histopathological changes of gingival tissues were observed by hematoxylin-eosin staining and the expressions of CCL20 and CCR6 were detected by immunohistochemistry (IHC) and quantitative real-time PCR (Q-PCR). SPSS 17.0 software package was used for statistical analysis.Histological observation showed that no significant histopathological change was found in the gingival tissues in all experimental groups. However, there were more infiltrated lymphocytes and neutrophils in the experimental groups. Normal gingival epithelial cells were hardly stained by anti-CCL20 but weakly stained by anti-CCR6. In the experimental groups, CCL20 could be detected in the basal layer of the gingival epithelial tissue, and CCR6 could be detected in the spinous layer and the basal layer of the gingival epithelium. The CCL20 and CCR6 expression in the gingival tissues of each experimental group were significantly higher than those of the control group, not only at the protein level but at the mRNA level (P0.05) except the CCL20 expression in the weightlessness group.Hypergravity exposure after 30 days of simulated weightlessness will not lead to significant pathological changes in gingival tissues, but can induce the expression of chemokine CCL20 and its receptor CCR6 in gingival tissue.