The protective effect of aminoguanidine on erectile function in diabetic rats is not related to the timing of treatment.
OBJECTIVE
To assess the accumulation of advanced glycation end products (AGEs) in streptozotocin (STZ)-induced diabetic rat cavernosal tissue, and to determine whether the protective effect of aminoguanidine (AG) on erectile function is related to the timing of treatment, as the accumulation of AGEs in the penis may be important in the pathogenesis of diabetes mellitus-induced erectile dysfunction, and prolonged treatment with AG (a selective AGE inhibitor), prevents erectile dysfunction in this situation.


METHODS
Harlan Sprague-Dawley rats were divided into groups 1-4, i.e. age-matched controls; STZ diabetic rats (60 mg/kg intraperitoneal) given free access to water; STZ diabetic rats treated with AG (1 g/L per day in the drinking water) immediately after inducing diabetes; and STZ-diabetic rats treated with AG 1 month after inducing diabetes, respectively. Two months after inducing diabetes the intracavernosal pressure was measured after cavernosal nerve stimulation, and cavernosal AGE (5-hydroxy methyl furfural, 5-HMF) levels assessed.


RESULTS
Cavernosal tissue 5-HMF levels from groups 2 and 4 were significantly higher than in group 1 (control). The expression of 5-HMF in group 3 was similar to that in group 1. Diabetic rats had significantly lower erectile function than controls, while groups 3 and 4 (treated with AG) had normal erectile function, as measured by cavernosal nerve stimulation.


CONCLUSIONS
The effect of AG on AGE levels seems to be time-dependent; that the 1-month treatment with AG improved erectile function with no change in AGEs suggests that AG has protective effects on the penile vasculature through alternative pathways.
Department of Urology, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112, USA.
Mustafa F
MF
Usta
Trinity J
TJ
Bivalacqua
I Turker
IT
Koksal
Behiye
B
Toptas
Sibel
S
Surmen
Wayne J G
WJ
Hellstrom
D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000150:complications* / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000627:therapeutic use*; D007172:Erectile Dysfunction / Q000517:prevention & control*; D017127:Glycation End Products, Advanced / Q000032:analysis / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006146:Guanidines / Q000627:therapeutic use*; D008297:Male; D010413:Penis / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D004791:Enzyme Inhibitors; D017127:Glycation End Products, Advanced; D006146:Guanidines; C004479:pimagedine