Lactated ringer's solution and hetastarch but not plasma resuscitation after rat hemorrhagic shock is associated with immediate lung apoptosis by theup-regulation of the bax protein

Background: We previously demonstrated that the type of resuscitation fluid used in hemorrhagic shock affects apoptosis. Unlike crystalloid, whole blo od seems to attenuate programmed cell death. The purpose of this study was to determine whether the acellular components of whole blood (plasma, album in) attenuated apoptosis and to determine whether this process involved the Bar protein pathway. Methods: Rats were hemorrhaged 27.5 mL/kg, kept in hypovolemic shock for 75 minutes, then resuscitated over 1 hour (n = 44). Control animals underwent anesthesia only (sham, n = 7), Treatment animals were bled then randomly a ssigned to the following resuscitation groups: no resuscitation (n = 6), wh ole blood (n = 6), plasma (:n = 6), 5% human albumin (n = 6), 6% hetastarch (n = 7), and lactated Ringer's solution (LR, n = 6), Hetastarch was used t o control for any colloid effect. LR was used as positive control. Immediat ely after resuscitation, the lung was collected and evaluated for apoptosis by using two methods. TUNEL stain was used to determine general DNA damage , and Bar protein was used to specifically determine intrinsic pathway invo lvement. Results: LR and hetastarch treatment resulted in significantly increased ap optosis in the lung as determined by both TUNEL and Bar expression (p < 0.0 5). Plasma infusion resulted in significantly less apoptosis than LR and he tastarch resuscitation, Multiple cell types (epithelium, endothelium, smoot h muscle, monocytes) underwent apoptosis in the lung as demonstrated by the TUNEL stain, whereas Bar expression was limited to cells residing in the p erivascular and peribronchial spaces. Conclusion: Apoptosis after volume resuscitation of hemorrhagic shock can b e affected by the type of resuscitation fluid used. Manufactured fluids suc h as lactated Ringer's solution and 6% hetastarch resuscitation resulted in the highest degree of lung apoptosis, The plasma component of whole blood resulted in the least apoptosis, The process of apoptosis after hemorrhagic shock resuscitation involves the Bar protein.