Anti-apoptotic effect of morphine-induced delayed preconditioning on pulmonary artery endothelial cells with anoxia/reoxygenation injury.
BACKGROUND
Opioid preconditioning (PC) reduces anoxia/reoxygenation (A/R) injury to various cells. However, it remains unclear whether opioid-induced delayed PC would show anti-apoptotic effects on pulmonary artery endothelial cells (PAECs) suffering from A/R injury. The present study was conducted to elucidate this issue and to investigate the potential mechanism of opioid-induced delayed PC.


METHODS
Cultured porcine PAECs underwent 16-hour anoxia followed by 1-hour reoxygenation 24 hours after pretreatment with saline (NaCl; 0.9%) or morphine (1 micromol/L). To determine the underlying mechanism, a non-selective K(ATP) channel inhibitor glibenclamide (Glib; 10 micromol/L), a nitric oxide (NO) synthase blocker NG-nitro-L-arginine methyl ester (L-NAME; 100 micromol/L), and an opioid receptor antagonist naloxone (Nal; 10 micromol/L) were given 30 minutes before the A/R load. The percentage of apoptotic cells was assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining. eNOS mRNA level was measured by real-time polymerase chain reaction (PCR). NO content of PAECs supernatants was measured with the Griess reagent.


RESULTS
Compared to the A/R PAECs, morphine-induced delayed PC significantly reduced PAECs apoptosis ((18.1 +/- 1.9)% vs (5.5 +/- 0.3)%; P < 0.05), increased NO release ((11.4 +/- 1.3) micromol/L vs (20.5 +/- 2.1) micromol/L, P < 0.05), and up-regulated eNOS gene expression nearly 9 times (P < 0.05). The anti-apoptosis effect of morphine was abolished by pretreatment with Glib, L-NAME and Nal, but the three agent-selves did not aggravate the A/R injury. Furthermore, L-NAME and Nal offset the enhanced release of NO caused by pretreatment with morphine.


CONCLUSIONS
Morphine-induced delayed PC prevents A/R injury of PAECs. This effect may be mediated by activation of K(ATP) channel via opioid receptor and NO signaling pathways.
Ding
Wen-gang
WG
Department of Anesthesiology, Second Hospital of Harbin Medical University, Harbin, Heilongjiang 150086, China.
Zhou
Hua-cheng
HC
Cui
Xiao-guang
XG
Li
Wen-zhi
WZ
Guo
Yue-ping
YP
Zhang
Bing
B
Liu
Wei
W
D000701:Analgesics, Opioid / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015687:Cell Hypoxia; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005905:Glyburide / Q000494:pharmacology; D020287:In Situ Nick-End Labeling; D009020:Morphine / Q000494:pharmacology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D010100:Oxygen / Q000494:pharmacology*; D011651:Pulmonary Artery / Q000166:cytology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013552:Swine
D000701:Analgesics, Opioid; D004791:Enzyme Inhibitors; D009292:Narcotic Antagonists; D012333:RNA, Messenger; D009569:Nitric Oxide; D009270:Naloxone; D009020:Morphine; D052250:Nitric Oxide Synthase Type III; D010100:Oxygen; D005905:Glyburide; D019331:NG-Nitroarginine Methyl Ester