Oxidative damage to proteins and decrease of antioxidant capacity in patients with varicocele

To examine oxidative damage to blood proteins in the spermatic vein and sem inal plasma antioxidant capacity of patients with varicocele, 30 young male patients with varicocele (group 1), 25 young male patients with subclinica l varicocele (group 2), and 15 normal young males without varicocele (group 3) were recruited in this study. Varicocele and subclinical varicocele wer e confirmed by physical examination and Doppler ultrasonography. Blood samp les were drawn from peripheral and spermatic veins before varicocelectomy. Plasma protein carbonyls were measured by a spectrophotometric assay after reacting with 2,4-dinitrophenylhydrazine. Protein thiols and ascorbic acid of seminal plasma were measured by spectrophotometric methods. We found tha t plasma protein carbonyls in the spermatic veins were significantly higher than those of corresponding peripheral veins in all 30 patients in group 1 and 12 patients in group 2 receiving varicocelectomy. Protein carbonyls in the spermatic veins of patients with varicocele (3.72 +/- 0.56 nmole/mg pr otein) and patients with subclinical varicocele (3.50 +/- 0.30 nmole/mg pro tein) were found to be higher than those of the control (2.35 +/- 0.33 nmol e/mg protein). Protein thiols were 0.97 +/- 0.96, 1.50 +/- 0.89, and 3.49 /- 0.81 nmole/ml, and ascorbic acid levels were 1.87 +/- 0.42, 2.13 +/- 0.2 4, and 2.38 +/- 0.07 mg/dl, in seminal plasma of the patients in groups 1, 2, and 3, respectively. Seminal plasma protein thiols and ascorbic acid lev els in group 1 were significantly lower than those in groups 2 and 3, respe ctively. These results indicate that oxidative stress in the patients with varicocele and subclinical varicocele was higher than that of the control. We suggest that plasma protein carbonyls, and protein thiols and ascorbic a cid of seminal plasma are useful markers for the assessment of oxidative st ress in patients with varicocele and subclinical varicocele. (C) 2001 Elsev ier Science Inc.