Modification of T cells function after restoration of spontaneous circulation in a rat model of cardiac arrest

Cardiac arrest?CA) is a prominent cause of mortality worldwide. A large number of patients after post-cardiac arrest is often associated with a phase of impaired immunity. Through an asphyxial cardiac arrest rat model, we investigate the peripheral blood T cells subsets and the expressions of surface molecules after restoration of spontaneous circulation (ROSC). Sprague-Dawley rats (weight, 300-400 g) were randomly divided into cardiac arrest (CA) group and sham-operated group. CA group rats were induced by 6 minutes of asphyxia. After successful ROSC, 24 surviving rats in two groups were randomly assigned to be sacrificed (n = 8 per subgroup) at 3, 24 and 72 h. The proportion of T cells and CD4+, CD8+ subsets as well as the expression of surface molecules (CTLA-4, PD-1, CD28) on T cells were identified by flow cytometry. The protein concentrations of cytokines (TNF-α, IL-6, IL-10, IL-4, IFN-γ, IL-17A) in serum were measured by ELISA. Compared with sham-operated control group, CD3+ lymphocytes in CA group were significantly decreased at 24 and 72 h post-ROSC. The expression levels of CD28, PD-1, and CTLA-4 on T cells were markedly increased in CA groups at 24 h post-ROSC. Additionally, the concentrations of IFN-γ were significantly declined, while IL-4 was markedly elevated in the CA group at 24 and 72 h post-ROSC. T cells function is moderately changed after CA, which is associated with decreased percentage of T cells, the upregulation of co-inhibitory molecules, and the shift from T helper (Th) 1 to Th2.