The administration of folic acid improves erectile function and reduces intracavernosal oxidative stress in the diabetic rabbit.
OBJECTIVE
To test the possibility that folic acid (FA) may be a means of treating erectile dysfunction (ED) in diabetes mellitus (DM), by studying the effect of FA administration to DM rabbits on cavernosal function and intrapenile oxidative stress.


METHODS
To investigate the effect of administering FA to DM rabbits on erectile function and oxidative stress the formation of superoxide (O(2)(-)), 8-isoprostane F(2 alpha) (8-IPF(2 alpha)) and prostacyclin (as 6-keto-PGF(1 alpha)) were assessed, as well as carbachol- and electrical field stimulated (EFS) relaxation and p47(phox) content (active component of NADPH oxidase complex). Non-ketotic DM was induced in New Zealand rabbits with alloxan and FA administered orally daily for 1 month. Rabbits were killed, penises excised and segments prepared. These were mounted in an organ bath and relaxation elicited with carbachol or EFS. O(2)(-) release was measured spectrophotometrically, p47(phox) expression by Western blotting and 8-IPF(2 alpha) and 6-keto-PGF(1 alpha) formation by enzyme-linked immunosorbant assay. Blood was collected for measurement of homocysteine, red blood cell (RBC) folate and glucose.


RESULTS
In cavernosal tissue from DM rabbits, carbachol-and EFS-induced relaxation was significantly impaired compared with the untreated controls. O(2)(-) release, p47(phox) expression and 8-IPF(2 alpha) formation were all enhanced and 6-keto-PGF(1 alpha) formation reduced compared with the controls. All these effects were reversed by FA. Plasma total homocysteine was reduced and RBC folate elevated.


CONCLUSIONS
The administration of FA may constitute a strategy for reducing ED in patients with DM.
Shukla
Nilima
N
Department of Cardiac Surgery, Bristol Royal Infirmary, Bristol, UK.
Hotston
Matthew
M
Persad
Raj
R
Angelini
Gianni D
GD
Jeremy
Jamie Y
JY
D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000494:pharmacology*; D015153:Blotting, Western; D003921:Diabetes Mellitus, Experimental / Q000150:complications; D004353:Drug Evaluation, Preclinical; D007172:Erectile Dysfunction / Q000188:drug therapy* / Q000503:physiopathology; D005492:Folic Acid / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects* / Q000502:physiology; D010410:Penile Erection / Q000187:drug effects* / Q000502:physiology; D011817:Rabbits; D016896:Treatment Outcome; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000494:pharmacology*
D000975:Antioxidants; D014665:Vasodilator Agents; D005492:Folic Acid