title: Endomorphins and ohmefentanyl in the inhibition of immunosuppressant function in rat peritoneal macrophages: An experimental in vitro study.
abstract: BACKGROUND
  The potential immunosuppressant effects of opioids might have clinical implications. The effects of endomorphins (EMs) and ohmefentanyl (OMF) on cultured rat peritoneal macrophages remain unclear.
  
  
  OBJECTIVE
  The aim of this study was to investigate the immunosuppressant effects of EMs and OMF on cultured rat peritoneal macrophages in vitro.
  
  
  METHODS
  Purified rat peritoneal macrophages, from healthy adult male Sprague-Dawley rats, were cultured with EM-1 (EM-1 group), EM-2 (EM-2 group), OMF (OMF group), and saline (saline group). We measured the concentrations of tumor necrosis factor (TNF)-α and interleukin (IL)-β in supernatant when macrophages were cultured with 10(-6) mol/L of EM-1, EM-2, OMF, or saline for 0, 6, 12, and 24 hours (time-effect relationship) or with 10(-10), 10(-9), 10(-8), 10(-7), and 10(-6) mol/L of these substances for 24 hours (concentration-effect relationship). We also determined the phagocytic and bactericidal activities of macrophages using isotope markers when macrophages were cultured with 10(-6) mol/L of EM-1, EM-2, OMF, or saline for 24 hours.
  
  
  RESULTS
  Compared with the saline group, TNF-α concentration decreased significantly in the OMF, EM-2, and EM-1 groups at 12 hours (P < 0.05, P < 0.05, and P < 0.01, respectively) and at 24 hours (P < 0.05, P < 0.01, and P < 0.01, respectively). Compared with the saline group, IL-1β concentration decreased signifcantly in the OMF, EM-2, and EM-1 groups at 12 hours (P < 0.05, P < 0.05, and P < 0.01, respectively) and at 24 hours (P < 0.05, P < 0.01, and P < 0.01, respectively). Decreased TNF-α and IL-1β concentrations were observed in the supernatant at 24 hours when cultured with 10(-8), 10(-7), and 10(-6) mol/L in the OMF and EM-2 groups (all, P < 0.05) and in the EM-1 group (all, P < 0.01). Compared with the saline group, macrophage phagocytic activity (all, P < 0.05) and macrophage bactericidal activity (all, P < 0.01) were significantly lower in the 3 experimental groups compared with the saline group.
  
  
  CONCLUSIONS
  In this in vitro experiment, EM-1, EM-2, and OMF inhibited the immunosuppressant function of cultured rat peritoneal macrophages, including decreasing TNF-α and IL-1β concentrations and phagocytic and bactericidal activities.
authors.affiliation: Department of Anesthesiology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, China.
authors.forename: Wei-Yan
authors.initials: WY
authors.lastname: Li
authors.affiliation: Department of Anesthesiology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, China.
authors.forename: Jian-Jun
authors.initials: JJ
authors.lastname: Yang
authors.affiliation: Department of Anesthesiology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, China.
authors.forename: Si-Hai
authors.initials: SH
authors.lastname: Zhu
authors.affiliation: Department of Anesthesiology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, China.
authors.forename: Hong-Jun
authors.initials: HJ
authors.lastname: Liu
authors.affiliation: Department of Anesthesiology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, China.
authors.forename: Jian-Guo
authors.initials: JG
authors.lastname: Xu
keywords: endomorphins; immunomodulator; macrophage; ohmefentanyl