Expression and activity of heme oxygenase-1 in artificially induced low-flow priapism in rat penile tissues.
BACKGROUND
The inducible isoform of heme oxygenase (HO)-1 regulates the vascular smooth muscle tone and responds to hypoxia.


OBJECTIVE
To investigate the role of HO-1 in a low-flow priapism.


METHODS
Sixty male Sprague-Dawley rats were divided into five groups of six rats each. Each group of rats was sacrificed at 0 hour (group 1, control), 4 hours (group 2), 8 hours (group 3), 12 hours (group 4), and 24 hours (group 5) after inducing an artificial veno-occlusive priapism. The changes of the expression and activity of HO-1, and the expression of inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS), and levels of cyclic guanosine monophosphate in the penis were examined in a low-flow priapism. In addition, the HO-1 expression level in the aortas from each group was simultaneously measured to determine whether the changes in HO-1 were systemic.


METHODS
The expression and activity of HO-1 was examined in artificially induced veno-occlusive priapism in rat penile tissues.


RESULTS
The expression of the HO-1 protein and the HO-1 enzyme activities in the penile tissues were gradually increased as time increased from 0 to 24 hours (P < 0.01). HO-1 immunoreactivities were localized in the endothelial layer of the cavernosal sinusoids. The expression of iNOS were also increased at 12 and 24 hours. The cyclic guanosine monophosphate level was also significantly increased at 24 hours (P < 0.05). However, the expression of the eNOS protein showed no statistically significant change with time, and the expression of the HO-1 protein in the aorta also showed no significant change with time.


CONCLUSIONS
A higher induction of HO-1 with time was observed in artificially induced veno-occlusive priapism, which might play a protective role against hypoxic injury. However, this may also play an important role in the vicious circle observed in a low-flow priapism.
Department of Pharmacology, School of Medicine, Gyeongsang National University Hospital, 90 Chilamdong, Jinju 660-702, South Korea.
Yong Chun
YC
Jin
Sung Chul
SC
Gam
Jae Hun
JH
Jung
Jung Suk
JS
Hyun
Ki Churl
KC
Chang
Jae Seog
JS
Hyun
D000818:Animals; D015153:Blotting, Western; D006152:Cyclic GMP / Q000032:analysis; D004730:Endothelium, Vascular / Q000473:pathology; D051547:Heme Oxygenase-1 / Q000032:analysis*; D008297:Male; D052247:Nitric Oxide Synthase Type II / Q000032:analysis; D052250:Nitric Oxide Synthase Type III / Q000032:analysis; D010413:Penis / Q000098:blood supply* / Q000473:pathology; D011317:Priapism / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D051547:Heme Oxygenase-1; D006152:Cyclic GMP