Early changes of CD4⁺CD25⁺Foxp3⁺ regulatory T cells and Th1/Th2, Tc1/Tc2 profiles in the peripheral blood of rats with controlled hemorrhagic shock and no fluid resuscitation.

Background: Hemorrhagic shock induces immune dysfunction. Regulatory T cells (Tregs), T-helper (Th) cells, and cytotoxic T-lymphocytes (CTLs) can execute many crucial actions in immune and inflammatory responses. This study was conducted to investigate the early pathophysiological changes of CD4(+)CD25(+)Foxp3(+) Treg and Th1/Th2, Tc1/Tc2 profiles in the peripheral blood of rats with controlled hemorrhagic shock and no fluid resuscitation.

Methods: A rat model of controlled hemorrhagic shock with no fluid resuscitation was established. Peripheral blood samples were taken before and four hours after hemorrhagic shock with no fluid resuscitation. Three color flow cytometry was used to detect Tregs, Th1, Th2, Tc1 and Tc2 cells in the samples.

Results: In the peripheral blood of rats, the percentage of Tregs four hours after hemorrhagic shock was significantly lower than before hemorrhagic shock (P = 0.001). The ratios of Th1/Th2 and Tc1/Tc2 were changed from (23.08 ± 8.98)% to (23.91 ± 15.36)%, and from (40.40 ± 21.56)% to (65.48 ± 23.88)%, respectively.

Conclusions: At an early stage, the advent of hemorrhagic shock is related to an early decrease of Tregs, and a mild shift in the Th1/Th2, Tc1/Tc2 balance toward Th1 and Tc1 dominance. These changes are part of a hyper-inflammatory state of the host, and will deteriorate the maintenance of immune balance. Further influences and detailed mechanisms need to be investigated.