Objective    The regulation of neuroendocrine hormones on the innate immune responses remains controversial. This report investigated whether the adrenal-derived hormones directly enhanced the innate immune responses and alternation of main pattern recognition receptors in adrenalectomized rats following blast injury.     Methods    Bilateral adrenalectomy was performed on Sprague-Dawley adult rats

who inflicted with mild blast wave injury in 7 d later. Peripheral blood leukocyte counting

macrophage phagocytosis

bacterial translocation (BT) in lungs

livers and mesenteric lymph nodes (MLN) were measured and analyzed

and TNF-α level in the lung tissue was detected. The mRNA expressions of scavenger receptor-A (SR-A)

CD14 and Toll like receptor-4 (TLR-4)  were assessed with RT-PCR.      Results    After blast injury

the number of peripheral leukocytes was decreased (P0.05)

and the phagocytosis of peritoneal macrophages was increased (P0.05)

which were both reversed by adrenalectomy (P0.05). The gut-derived BT

TNF-α secretion were elevated in adrenalectomized rats (P0.05). Furthermore

the mRNA levels of SR-A

CD14 and TLR-4 in lung tissues of adrenalectomized rats were all decreased significantly. Adrenalectomized rats showed enhancement of inflammatory responses and severe tissue injuries.     Conclusion    Our data strongly indicate that the adrenal hormones can enhance the innate immune responses to the blast wave injury

at least partially via SR-A

CD14 and TLR-4.