Date Published: September 11, 2012
Publisher: Hindawi Publishing Corporation
Author(s): Antonio Mancini, Roberto Festa, Sebastiano Raimondo, Andrea Silvestrini, Elena Giacchi, Gian Paolo Littarru, Alfredo Pontecorvi, Elisabetta Meucci.
Oxidative stress is a mechanism underlying different kinds of infertility in human males. However, different results can be observed in relation to the method used for its evaluation. Varicocele patients show a number of biochemical abnormalities, including an altered distribution of coenzyme Q between seminal plasma and sperm cells and also an apparent defect in the utilization of antioxidants. Moreover, an influence of systemic hormones on seminal antioxidant system was observed too. Finally, the effects of surgical treatment on oxidativestress indexes and the possible usefulness of some medical therapies, like coenzyme Q supplementation, are discussed. In conclusion, published data show a role of oxidative stress in varicocele-related male infertility, but at present we do not know the precise molecular mechanisms underlying these phenomena.
An excess of reactive oxygen species (ROS) and other oxidant radicals, in the body but in particular at genital level, has been associated with male infertility [1–5]. The high content of polyunsaturated fatty acids within the spermatozoa plasma membrane and the low concentration of cytoplasmic scavenging enzymes make these cells highly susceptible to peroxidation in the presence of high levels of ROS in seminal fluid [6–8]. It has been shown that the time of permanence of spermatozoa in the epididymis is longer in oligozoospermic patients, resulting in a higher exposure to ROS [9–11]. The source of ROS in seminal fluid is due to both sperm cells and infiltrating leukocytes . There is also a correlation between leukocyte concentrations, ROS levels, lipid peroxidation, and functional damage .
Varicocele (VAR) is a model of male infertility particularly interesting, from the andrological point of view, not only for its prevalence (19–41% of infertile men)  but also in relation to an open debate on the real need of surgical or sclerotherapic treatment and on its role in causing infertility. Furthermore, different studies suggest that OS is a common mechanism underlying VAR, as well as X-irradiation, exposure to environmental toxicants, or other physical conditions such as cryptorchidism. All these stress conditions can cause changes in testicular microvascular blood flow and endocrine signalling, eventually leading to germ cell apoptosis and hypospermatogenesis .
The effect of varicocelectomy on OS, similarly, is not so univocally clear. Vitamin E has been demonstrated to be positively affected by surgical VAR repair . The relationship between varicocelectomy and plasma OS has been studied also in children (10–16 years) with left-sided VAR and ipsilateral testicular hypoplasia, by evaluating basal (presurgery) thiobarbituric acid reactive substances and plasma peroxidation susceptibility (lag time and slope) both in peripheral blood samples and in samples from the pampinous plexus. Peripheral blood samples were re-evaluated 1 year after surgery. Both parameters were comparable in peripheral and pampinous blood and higher compared with controls. After surgery they significantly decreased, again suggesting that surgical varicocelectomy with a venous shunt construction reduces OS. The study highlights that OS is present in children and adolescents with VAR .
The findings mentioned in the previous paragraphs constitute the rationale for treating infertile subjects, particularly VAR, with exogenous CoQ.
Even if it is clear that Oxidative Stress is present in varicocele as a pathogenic mechanism, however the interpretation of analytical data is not so simple. In fact, antioxidants values can be influenced by different modulatory factors, and anyway they always represent the balance between synthesis and utilization.