Effects of plasma Hcy on the contents of CO and HO-2 in the corpus cavernosum of ED rats with hyperhomocysteinemia / 中华男科学杂志

<p><b>OBJECTIVE</b>To study the changes in the activities of carbon monoxide (CO) and heme oxygenase 2 (HO-2) in ED rats with hyperhomocysteinemia (HHcy).</p><p><b>METHODS</b>This study included 40 male Wistar rats weighing 280 - 310 g, 10 as normal controls (group A). HHcy models were made in the other 30 by giving 3% methionine for 4 weeks, and then divided into groups B, C and D. The rats in group B continued to be fed with 3% methionine, those in group C were treated with betaine hydrochloride, and those in group D were given zinc porphyrin IX at 45 micromol per kg per d. Penile erections of the rats were recorded, and 4 weeks later, all were killed for determination of the levels of homocysteine (Hcy) in the blood plasma and the activities of CO and HO-2 in the corpus cavernosum of the penis.</p><p><b>RESULTS</b>The level of plasma Hcy, penile erection frequency and the content of CO in the corpus cavernosum were (12.55 +/- 0.82) micromol/L, (1.88 +/- 0.05) times and (10.55 +/- 1.73) micromol/L in group A, the Hcy level significantly higher while the penile erection frequency and CO content remarkably lower than in group B ([25.01 +/- 0.94] micromol/L, [0.70 +/- 0.05] times and [9.51 +/- 1.52] micromol/L, P < 0.05 or P < 0.01), with a negative correlation between the level of Hcy and that of CO and HO-2 (P < 0.01). Compared with group B, the three parameters were all significantly increased in C ([14.37 +/- 0.47] micromol/L, [1.18 +/- 0.08] times and [10.36 +/- 1.56] micromol/L, all P < 0.05 or P < 0.01).</p><p><b>CONCLUSION</b>Decreased expressions of CO and HO-2 in the corpus cavernosum of the penis may result in ED in HHcy rats. Betaine can reduce the Hcy level in the blood plasma and CO content in the corpus cavernosum, which might be one of the mechanisms of its action on ED with HHcy.</p>

Correlation of homocysteine in plasma with NOS and endogenous CO in the penile corpus cavernosum of type 2 diabetic rats / 中华男科学杂志

<p><b>OBJECTIVE</b>To study the correlation of homocysteine (Hcy) in plasma with nitric oxide synthetase (NOS) and endogenous carbon monoxide (CO) in the penile corpus cavernosum of type 2 diabetic rats.</p><p><b>METHODS</b>This study included 40 male Wistar rats, 10 as controls (Group A) and the other 30 as diabetes mellitus (DM) models. Four weeks after the model establishment, the model rats were divided into a DM group (Group B, n = 10), an insulin treated group (Group C, n = 10), and a folic acid and vitamin B12 treated group (Group D, n = 10). All the rats were injected with apomorphine and observed for penile erection at 8 and 12 weeks, and the levels of total plasma Hcy (tHcy), NOS and CO in the penile corpus cavernosum were measured at 12 weeks.</p><p><b>RESULTS</b>Compared with Group A, the level of tHcy was significantly increased, while NOS and CO activities in the penile cavernous tis-sue and erectile function remarkably decreased in Group B (P < 0.01). The incidence rate of high Hcy was 55% in the DM rats. In comparison, the level of tHcy was obviously decreased, and the NOS activity and erectile function markedly increased in Groups C and D (P < 0.01). The Hcy level showed a significant negative correlation with NOS activity (rA = -0.89, rB = -0.76, rc = -0.91, rD = -0.91) and CO content (TA = -0.82, r, = -0.77, rc = -0.93, rD = -0.81).</p><p><b>CONCLUSION</b>High plasma Hcy can decrease NOS and CO activities in the penile corpus cavernosum, and consequently induce erectile dysfunction in DM rats, while insulin, folic acid and vitamin B12 can improve their penile erectile function by increasing NOS and CO activities.</p>

Aging reduces contents of endogenous CO, cAMP and cGMP in rat penile tissues / 中华男科学杂志

<p><b>OBJECTIVE</b>To explore the relationship of aging with the changes of endogenous carbon monoxide (CO), cGMP and cAMP contents in the penile tissues of rats.</p><p><b>METHODS</b>Twenty-four male rats were equally divided into an 8-month, a 16-month and a 24-month group, and their penile erection was detected by injecting apomorphine, their penile cavernous body harvested, and the contents of CO, cAPM and cGMP detected by improved dual wavelength spectrophotometry.</p><p><b>RESULTS</b>The contents of CO, cAPM and cGMP were reduced with the increase of age, with statistically significant differences between the three age groups (P < 0.01).</p><p><b>CONCLUSION</b>Aging significantly decreased the contents of CO, cAMP and cGMP in the penile tissues of the rats, which suggests that aging might play an important role in erectile dysfunction.</p>