[Expressions of NOS isoforms in the cavernous tissues of diabetic rat models].
OBJECTIVE
To investigate the mechanism of diabetic erectile dysfunction (ED) and find new methods for its treatment by detecting the changes in nitric oxide synthase (NOS) isoforms and erectile function of diabetic rats and observing the effects of insulin and alpha-lipoic acid (LA) on it.


METHODS
Fifty male Sprague-Dawley rats were divided into Groups A (normal control, n=10), B (non-intervention diabetes mellitus, n=13), C (insulin intervention diabetes mellitus, n=12), and D (insulin + LA intervention, n=15). And the diabetic models were made by intraperitoneal injection of streptozocin (STZ). Eight weeks later, the erectile function of the rats was assessed following apomorphine injection and the contents of NOS isoforms in the erectile tissues measured by immunohistochemical staining.


RESULTS
All the rats of Group A showed a normal erectile function (100%). In comparison, those in Groups B, C and D exhibited a significantly decreased rate, 28.6% in Group B, 62.5% in Group C and 80.9% in Group D. The numbers of positive nNOS fibers and eNOS in the penile tissues per visual field were 86.7 and 9.6 in Group A, but only 36.5 and 3.3 in Group B, 52.7 and 5.7 in Group C, and 71.4 and 7.4 in Group D (P < 0.05). However, the expression of iNOS was significantly lower in Group A (6.9) than in Groups B (43.6), C (36.2) and D (19.3) (P < 0.05). Compared with Groups B and C, the erectile function and the expressions of nNOS and eNOS were markedly increased, while the expression of iNOS significantly decreased in Group D (P < 0.05).


CONCLUSIONS
Diabetes mellitus severely affects penile erectile function and the expressions of NOS isoforms in the cavernous tissues, for which hyperglycemia is mainly responsible. LA is proved obviously efficacious for diabetic ED, which might be related to its antioxidant effect.
Yao
Le-shen
LS
Department of Urology, Drum Tower Hospital Affiliated to Nanjing University School of Medicine, Nanjing, Jiangsu 210008, China. yls7366@163.com
Wang
Yang-tian
YT
Chen
Yun
Y
Dai
Yu-tian
YT
D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism* / Q000503:physiopathology; D007172:Erectile Dysfunction / Q000378:metabolism* / Q000503:physiopathology; D007328:Insulin / Q000494:pharmacology; D008297:Male; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D010410:Penile Erection; D010413:Penis / Q000378:metabolism / Q000503:physiopathology*; D020033:Protein Isoforms; D051381:Rats; D017207:Rats, Sprague-Dawley; D008063:Thioctic Acid / Q000494:pharmacology
D007328:Insulin; D020033:Protein Isoforms; D008063:Thioctic Acid; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D052250:Nitric Oxide Synthase Type III; C496322:Nos1 protein, rat; C496316:Nos3 protein, rat