title: Improved survival in uncontrolled hemorrhagic shock induced by massive splenic injury in the proestrus phase of the reproductive cycle in the female rat.
abstract: Estrogen has a protective effect in adverse circulatory conditions such as trauma-hemorrhage and ischemia-reperfusion. In the present investigation uncontrolled hemorrhagic shock induced by massive splenic injury (MSI) was studied in male and female rats during the proestrus and metestrus phase of the reproductive cycle. The animals were anesthetized and randomly divided into four groups: group 1 (n = 8) were sham operated female animals; in group 2 (n = 8) MSI was induced in male animals; in group 3 (n = 8) MSI was induced in female animals in proestrus; in group 4 (n = 8) MSI was induced in female animals in metestrus. Plasma 17beta-estradiol was 112.8 +/- 16.7 pg/mL in group 3 and 44.8 +/- 16.7 pg/mL in group 4 (P < 0.04). After MSI the mean arterial pressure dropped in group 2 from 135.6 +/- 3.9 to 47.6 +/- 8.8 mmHg (P < 0.001) in 60 min. Total blood loss in 4 h was 29.6 +/- 3.5% of blood volume and mean survival time 161.3 +/- 30.6 min. In group 3 total blood loss in 4 h was 24.4 +/- 5.7% of blood volume and mean survival time 240 +/- 0 min (P < 0.03 compared with group 2). In group 4, total blood loss in 4 h was 29.6 +/- 3.9% of blood volume and mean survival time was 112.3 +/- 28.7 min (P < 0.001 compared with group 3). These results indicate that female rats in the proestrus phase of the reproductive cycle better maintain hemodynamic stability and survival in uncontrolled hemorrhagic shock than female animals in metestrus or males. This difference is attributed to factors other than blood loss.
authors.affiliation: Department of Surgery A, Laboratory for Shock and Trauma Research, Rambam Medical Center, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel. m_krausz@rambam.health.gov.il
authors.forename: Michael M
authors.initials: MM
authors.lastname: Krausz
authors.forename: Yulia
authors.initials: Y
authors.lastname: Bashenko
authors.forename: Mark
authors.initials: M
authors.lastname: Hirsh
mesh_terms: D000818:Animals; D001794:Blood Pressure; D004958:Estradiol / Q000097:blood; D030762:Estrous Cycle / Q000097:blood*; D005260:Female; D006339:Heart Rate; D006400:Hematocrit; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008686:Metestrus / Q000097:blood; D019106:Postoperative Hemorrhage; D011359:Proestrus / Q000097:blood*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012771:Shock, Hemorrhagic / Q000209:etiology / Q000401:mortality*; D013161:Splenic Rupture / Q000150:complications*; D015996:Survival Rate
chemical_list: D019344:Lactic Acid; D004958:Estradiol