Efeito da varicocele na função dos espermatozóides. / Effect of varicocele on sperm function.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Objectives: to assess the effect of varicocele on sperm nuclear DNA integrity, mitochondrial activity, lipid peroxidation and acrosome integrity. Methods: semen samples were obtained and analyzed according to the World Health Organization guidelines (1999) and sperm morphology was evaluated by Krugers strict criteria (1986). The study group included 30 men with varicocele grades II or III and the control group included 32 men without varicocele. Sperm nuclear DNA integrity was assessed by the alkaline Comet assay, and cells were graded according to the intensity of DNA damage: class I (high DNA integrity), class II (DNA still intact or initiating fragmentation), class III (DNA fairly fragmented) and class IV (DNA extremely fragmented). Mitochondrial activity was evaluated by the colorimetric method proposed by Hrudka (1987). Cells were classified according to the proportion of active mitochondria: class I (100% of active mitochondria), class II (more than 50% of active mitochondria), class III (less than 50% of active mitochondria) and class IV (100% of inactive mitochondria). Lipid peroxidation was determinated by Ohkawas method, which is based on the measurement of malondialdehyde (MDA) due to its reaction with thiobarbituric acid (TBA), and the levels of lipid peroxidation were described as nanograms of TBARS/mL. Acrosome integrity was assessed by use of the conjugated fluorescent probe PNA-FITC and the results were expressed in percentages of intact acrosomes (fluorescence was observed over the entire acrosomal region of the sperm head). Results: Concerning DNA integrity, the varicocele group showed less spermatozoa with intact nuclear DNA (grade II, p=0,040). There was no significant difference in classes I, III and IV between the two groups. Regarding mitochondrial activity the varicocele group showed more cells with inactive mitochondria (class III, p=0,001) and less cells with active mitochondria (class I, p=0,005). There was no difference in classes II and IV. Also, the varicocele group showed less spermatozoa with intact acrosomes (p=0,0002), when compared to the controls. Finally, no significant differences were observed in lipid peroxidation levels. Conclusions: This study was able to demonstrate that varicocele in adults is associated with increased DNA fragmentation, reduced mitochondrial activity and decreased acrosome integrity even when semen quality does not differ from men without varicocele. However, levels of seminal products of lipid degradation (MDA) are not increased in these patients, suggesting that perhaps the functional changes found are not directly associated with oxidative stress, or that oxidative stress leads to changes in DNA, acrosomes and mitochondria during spermatogenesis, and not after ejaculation.

ASSUNTO(S)

1. varicocele. 2. espermatozóide. 3. estresse oxidativo. 4. acrossomo. 5. dano no dna. 6. mitocôndrias/metabolismo. varicocele, spermatozoa, oxidative stress, acrosome, dna damage, mitochondria/metabolism. medicina

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