The effect of hyperbaric oxygen on the function of peritoneal macrophages in septic mice

Abstract

Objective To investigate the changes of peritoneal macrophage function in sepsis mice after hyperbaric oxygen (HO) therapy. Methods One hundred C57BL/6 mice were randomly(random number) divided into four groups in equal number (n=25): control group (normal saline), sepsis group,hyperbaric oxygen group, sepsis+ hyperbaric oxygen group; the sepstic mice were treated by intra-peritoneal injection with zymosan; The mice of hyperbaric oxygen group and sepsis+ hyperbaric oxygen group received hyperbaric oxygen therapy (2 atm, 2 h, 100% O2). The number of surviving mice was obsevred at 72 h after the intra-peritoneal injection with zymosan; The percentage of M1 macrophage was detected by flow cytometry. The expression of mRNA of inducible nitric oxide synthase (iNOS) in peritoneal macrophage was detected with RT-PCR. The levels of IL-12 and IL-10 in peripheral blood were measured by ELISA. Results Compared with sepsis group, the number of surviving mice of sepsis+ hyperbaric oxygen group was significantly higher (9 vs. 16, P<0.01). The percentages of M1 macrophage in sepsis+ hyperbaric oxygen group was significantly lower than that in sepsis group [(4.75±0.14)% vs. (2.25±0.16)%, F=803.438, P<0.01]. The expression of mRNA of inducible nitric oxide synthase(iNOS) in sepsis+ hyperbaric oxygen group were significantly lower than that in sepsis group [(39.62±1.74) vs. (48.32±3.34), F=31.992, P<0.01]. The level of IL-12 in peripheral blood in sepsis+ hyperbaric oxygen group was significantly lower than that in sepsis group [(242.62±19.10) pg/mL vs. (159.51±6.35)pg/mL, F=102.282, P<0.01]. The level of IL-10 was significantly higher than that in sepsis group [(521.26±6.3) pg/mL vs. (188.83±8.53) pg/mL, F=5 896.006, P<0.01]. Conclusions Hyperbaric oxygen therapy had effective effect on increasing the number of surviving mice of sepsis group, reducing the level of IL-12 in peripheral blood and rising the level of IL-10 in peripheral blood. By inhibiting the expression of M1 macrophage and iNOS, hyperbaric oxygen could reduce the excessive inflammatory response and play a role in the protection of mice. Key words: Hyperbaric oxygen; Sepsis; Peritoneal macrophages; Inducible nitric oxide synthase; Interleukin-12; Interleukin-10