Sex differences in response to immunonutrition in sepsis

Background: Cell-mediated immune response is superior in females compared to males. Whether sex differences influenced mortality in sepsis while on immune-enhancing nutrients was investigated. Materials and Methods: Seventy-two non-orchitectomized male and non-oophorectomized female rats (n = 36/group) were randomized into four groups. Rats were fed either an immune-enhancing diet or control diet for five days. Sepsis was induced with caecal ligation and puncture (CLP). An additional group of orchitectomized and oophorectomized rats (n = 36/group) were divided into four groups; fed either an immune-enhancing or control diet of one month, then following castration. Sepsis was induced with CLP. The influence of immune-enhancing nutrients on the effect of the rat's sex on mortality rates and serum cytokines were compared. Results: Non-orchitectomized male rats had a decreased mortality (88.9% vs. 16.7%) on immune-enhancing diet. Low mortality among non-oophorectomized female rats persisted, on immune-enhancing diet (27.8% vs. 11.1%). Orchitectomized rats demonstrated reduced mortality (88.8% vs. 50%) on immune-enhancing diet. Oophorectomized rats showed a similar trend (55.6% vs. 44.4%). Orchitectomy increased mortality in spite of immune-enhancing diet (50% vs. 16.7%). Oophorectomy increased mortality on immune-enhancing diet (44.4% vs. 11.1%). Circulating IL-1β was higher in non-oophorectomized female rats on control diet compared to immune-enhancing diet. Non-orchitectomized male and non-oophorectomized female rats had similar increases in IL-10 on immune-enhancing diet. Conclusions: Mortality rates on immunonutrition were less in male than female rats following sepsis. Orchitectomy did not confer an advantage for septic rats. Sex hormone was more important than immunonutrition in septic female rats.