Estradiol administration after trauma-hemorrhage improves cardiovascular and hepatocellular functions in male animals

Objective To determine whether female sex steroids have any salutary effects on the d epressed cardiovascular and hepatocellular functions following trauma and h emorrhage in male animals. Summary Background Data Studies indicate that gender difference exists in the immune and cardiovasc ular responses to trauma-hemorrhage, and that male sex steroids appear to b e responsible for producing immune and organ dysfunction, but it remains un known if female sex steroids produce any salutary effects on the depressed cellular and organ functions in males following trauma and hemorrhage. Method Adult male Sprague-Dawley rats underwent a midline laparotomy (i.e., trauma induction), and were bled to and maintained at a mean arterial pressure of 40 mmHg until 40% of the maximum bleed-out volume was returned in the form of Ringer's lactate (RL). Animals were then resuscitated with RL at 4 lime s the shed blood over 60 minutes. 17 beta -Estradiol (50 mug/kg) or an equa l volume of vehicle was injected subcutaneously 15 minutes before the end o f resuscitation. The maximal rate of ventricular pressure increase or decre ase (+/-dP/dt(max)), cardiac output, and hepatocellular function (i.e,, max imal velocity and overall efficiency of in vivo indocyanine green clearance ) were assessed at 24 hours after hemorrhage and resuscitation. Plasma leve ls of interleukin (IL)-6 were also measured. Results Left ventricular performance, cardiac output, and hepatocellular function d ecreased significantly at 24 hours after trauma-hemorrhage and resuscitatio n. Plasma levels of IL-6 were elevated. Administration of 17 beta -estradio l significantly improved cardiac performance, cardiac output, and hepatocel lular function, and attenuated the increase in plasma IL-6 levels. Conclusion Administration of estrogen appears to be a useful adjunct for restoring car diovascular and hepatocellular functions after trauma-hemorrhage in male ra ts.