Differences in the expression of LPS-receptors are not responsible for the sex-specific immune response after trauma and hemorrhagic shock

Several studies demonstrated a sex-specific cytokine secretion by macrophages following trauma–hemorrhage (T–H) and incubation with lipopolysaccharide A (LPS). Although LPS is known to act via the receptors CD14 and TLR4 on macrophages, it remains unknown whether differences in LPS receptor expression in males and females may be responsible for the gender-specific LPS induced cytokine response following (T–H). To study this, male and proestrus female mice (C3H/HeN) were subjected to trauma (laparotomy) followed by hemorrhage or sham operation. At 2 h thereafter, SMϕ and PMϕ were harvested and cultured for 2 h. The expression of CD14 and TLR4 was measured by flow cytometry on unstimulated SMϕ and PMϕ as well as after LPS stimulation. The results indicate that the expression of CD14 and TLR4 on SMϕ and PMϕ from female and male mice was similar in sham-operated animals and after (T–H). Incubation of macrophages with LPS did not alter CD14 and TLR4 expression in the study groups. Thus, the sex specific LPS induced cytokine secretion after (T–H) is not caused by differences in LPS receptor expression on Mϕ of male and female mice.