Changes in invariant nature kiler T (iNKT) cell percentages and subsets in immune organs of mice at different stages of obesity / 中华微生物学和免疫学杂志

ABSTRACT

Objective:To observe the changes in percentages and subsets of invariant nature kiler T (iNKT) cells in adipose and related tissues at different stages of obesity, and analyze the role of iNKT cells during chronic inflammation in adipose tissues in a mouse model of obesity established with high-fat diet.Methods:Changes in mouse body weight, mental state, glucose tolerance and insulin tolerance were recorded. Hematoxylin and eosin (HE) staining was used to observe pathological changes in adipose tissues. Flow cytometry was performed to detect the percentages and subsets of iNKT cells as well as the percentages and subtypes of macrophages. The levels of cytokines in serum samples and the culture supernatants of lymphocytes in adipose tissues were detected with CBA. The expression of related proteins in adipose tissues was detected by Western blot.Results:(1) The volume of adipose cells increased significantly after four weeks of high-fat feeding, but the infiltration of inflammatory cells was not obvious. Significantly increased infiltration of inflammatory cells was observed after 12 weeks of high-fat feeding. (2) High-fat feeding could reduce the percentage of iNKT cells, increase the proportion of iNKT1 subgroup and decrease the proportion of iNKT10 subgroup in adipose tissues. The proportion of iNKT1 subgroup in thymus increased, but that of iNKT2 subgroup decreased. The percentage of macrophages and the proportion of M1 subgroup in adipose tissues increased, while the proportion of M2 subgroup decreased, which were more obvious after 12 weeks of high-fat feeding. (3) High-fat feeding resulted in decreased expression of E4BP4 and arginase-1 (Arg-1) in adipose tissues and increased expression of inducible nitric oxide synthase (iNOS). (4) High-fat feeding significantly increased the pro-inflammatory cytokines and decreased the anti-inflammatory cytokines in mouse serum and culture supernatants of lymphocytes in adipose tissues with more significant changes observed after 12 weeks of high-fat feeding.Conclusions:Increased iNKT1 and decreased iNKT10 in obese adipose tissues might be closely related to the increased M1 polarization and the imbalance of iNKT subsets might be involved in the progression of chronic inflammation in obese adipose tissues.