Asthenozoospermia is a condition in which the percentage of progressively motile sperm is abnormally low. In men, it is defined as less than 25% rapid motility or less than 50% progression in a semen sample 1.
The following represent the lower limits of normal semen: semen volume, 1.5 ml (1.4–1.7); total sperm number, 39 million per ejaculate (33–46); sperm concentration, 15 million per ml (12–16); vitality, 58% live (55–63); progressive motility, 32% (31–34); total (progressive+nonprogressive) motility, 40% (38–42); and morphologically normal forms, 4.0% (3.0–4.0) 2.
No definite or appropriate treatment for idiopathic male infertility has been found; neither have any controlled, double-blind studies reported any significant improvement in pregnancy rates following the use of hormones or hormone analogues. In addition to endocrine aspects, the influence of reactive oxygen species (ROS) on fertility has become of increasing interest. In patients with asthenozoospermia, an elevated production of ROS in seminal plasma and increased ROS-mediated damage of sperm membranes have been detected, but the origin of these effects is unknown 3. It is still unclear at which point the peroxidative damage to spermatozoa occurs, whether within semen (during the time required for liquefaction), in the epididymis (where spermatozoa are stored before ejaculation), or in the testis. By altering membrane integrity, ROS may impair sperm motility as well as sperm viability 4. Therefore, protective agents against ROS may be useful therapeutic agents in the treatment of male infertility.
α-Lipoic acid (ALA) is unique in its ability to act as an antioxidant in fat-soluble and water-soluble tissues in both its oxidized and reduced forms. Because of the low redox potential of the lipoate/dihydrolipoate system, reduced ALA participates not only in reactions neutralizing ROS but also in the reduction of oxidized forms of other antioxidants. For this reason, ALA is called a typical antioxidant 5. Also, it has been suggested that ALA functions indirectly as an antioxidant by downregulating ‘prooxidant’ enzymes such as inducible nitric oxide synthase and xanthine oxidase 6. However, many cases of male infertility have been suggested to be a consequence of earlier episodes of testicular autoimmunity 7. The immune-modulatory effects of ALA have been studied by several laboratories in its inhibitory effect on human T-cell migration 8. ALA has been used successfully in experimental animals to protect against the oxidative stress induced by X-ray and chemotherapeutic agents 9,10.
ALA has been used as an in-vitro agent to increase the sperm capability of fertilization 11.
This work aims to evaluate in vivo the efficacy of ALA in idiopathic asthenozoospermia, either isolated or as a part oligoasthenozoospermia.
Patients and methods
This study included 60 patients with a complaint of infertility, with the main semen pathology being asthenozoospermia, either isolated or with oligozoospermia. All patients were selected from among the attendants of the outpatient clinic of the andrology and STDs Department, Kasr El-Aini hospital, Cairo University.
The patients were selected on the basis of the following criteria:
History of infertility for more than 1 year, sperm concentration more than 5 million sperms/ml, low motility: less than 32% progressive motility and less than 40% progressive and nonprogressive motility, no clinical or duplex evidence of varicocele, no evidence of genitourinary tract infection, no clinical symptoms of endocrinal or genetic disorders (e.g. Klinefelter’s syndrome), normal serum follicle-stimulating hormone and testosterone levels, no history of medical diseases (e.g. diabetes, hypertension, liver, or kidney diseases), no concurrent intake of fertility-enhancing medication, and no history of chemotherapeutic medications.
The 60 patients were divided into two groups of 30 patients each.
For each patient in either group, the following were carried out in sequence after obtaining written consent:
- Full history taking including personal history (age, residence, occupation), marital history, and type of infertility, previous history of genital tract infection, special habits, previous drug intake, history of previous abortions, and history of chemical exposure.
- Full general examination including the general condition, weight, height, span, body proportions, fat distribution, gynecomastia, blood pressure, and abdominal examination.
- Full local examination in the upright and supine positions.
- For each of the two groups, semen analysis was carried out at baseline twice using the conventional method and computer-assisted semen analysis system (CASA, WLJY-9000, Weili Sperm Quality Analysis System; Beijing Weili Century Science & Tech. Deve. Co. Ltd, Beijing, China) according to WHO (2010) standards. Semen analysis for each patient was repeated monthly during the 3-month clinical trial (0=baseline, 1=end of the first month, 2=end of the second month, 3=end of the third month):
- Quantitative analysis of the length of sperm’s major axis, minor axis, acrosome integrality ratio, and sperm area.
- Morphological classification according to sperm characteristics with manual modification.
- Quantitative results of sperm morphological parameters can be obtained according to WHO standards.
- Expressed prostatic smear and two glass urine tests were carried out to exclude infection.
- One group was given oral ALA tablets at a dose of 300 mg twice/day (Thiotacid 300 mg; Eva Company, Cairo, Egypt), whereas the other group was given a placebo twice daily. The duration of therapy for both groups was 3 months, which is the time for a complete spermatogenic cycle. The study was carried out on a double-blind basis, where neither the patient nor the researcher knew the drug from the placebo. The drug and the placebo were given to patients in numbered bottles.
The primary outcome measures were the improvements in sperm concentration, sperm motility, and progressive motility. The secondary outcome measure was the pregnancy rate during the 3-month therapy with ALA.
Data were statistically described in terms of range, mean and SD, frequencies (number of cases), and percentages when appropriate. Comparison between the study groups was carried out using the Student t-test. For comparison of categorical data, the χ 2-test was carried out. Fisher’s exact test was used when the expected frequency was less than 5. A P value less than 0.05 was considered statistically significant. All statistical calculations were carried out using the computer programs Microsoft Excel 2007 (Microsoft Corporation, New York City, New York, USA) and statistical package for the social science (SPSS Inc., Chicago, Illinois, USA) version 15 for Microsoft Windows.
The current prospective study included 60 asthenozoospermic (32 isolated athenozoospermia and 28 oligoathenozoospermia) patients divided into two equal groups. Only 48 patients completed the entire 3 months of the clinical trial, 24 in each group. After decoding, it was found that group A received the active drug whereas group B received a placebo. The dropout rate was 20% mainly because of failure of compliance. No adverse events were reported by the patients during the 3 months of the clinical trial.
There was no statistically significant difference between both groups in terms of age, smoking, duration of infertility, and semen parameters before the start of therapy (Table 1).
No statistically significant difference was found after the first month of the trial in any of the semen parameters studied. From the second month, a statistically significant difference was found between the active group and the placebo group in the sperm counts (P=0.042), but there was no difference in sperm motility. Sperm count at the end of the third month of drug therapy had improved significantly (P=0.001), with no difference in the motility and the abnormal forms between both groups (Table 2).
Five patients (20.8%) from the active group receiving ALA achieved pregnancies; however, only two patients (8.39%) achieved pregnancies from the placebo group. All pregnancies occurred during the last 40 days of treatment.
The P values for pregnancy were statistically insignificant (P=0.220) between the active and the placebo group. This is probably because of the small number of pregnancies that occurred in the groups.
In the active group, four of five patients who impregnated their wives showed an improvement in both count and motility.
The active group
In the active group, a statistically significant improvement occurred in count, total motility, progressive motility, and abnormal forms after 2 and 3 months of therapy compared with the pretreatment values. This improvement started at the end of the first month and reached the maximum value during the second and third months of therapy (Tables 1–3).
Improvement in progressive and total motility led us to examine the types of motility improvement more in detail. It was found that improvement in the VCL, VSL, and VAP started from the second month of therapy and reached a maximum during the third month. Maximum improvements were for the VCL and VSL (P<0.001) (Table 4).
This is the first worldwide clinical trial to examine the effect of ALA on semen parameters of idiopathic athenozoospermia and oligoathenozoospermia cases.
Idiopathic oligoasthenoteratozoospermia is related to defective spermatogenesis, the origin of which is unknown and often considered as undetectable by common laboratory methods. A large number of idiopathic oligoathenoteratozoospermia infertile patients have a normal physical examination, normal hormonal profile, and no evident cause of their subfertile status 12,13.
Impaired spermatogenesis leads to abnormal spermatozoa and yields excess ROS, which can overwhelm and deplete the antioxidant defenses, and results in oxidative stress in patients with idiopathic asthenozoospermia 14,15. Kumar et al. 16 have reported that the ROS level in an idiopathic oligoathenozoospermia group was higher than that of the fertile control group (P<0.01). There was a negative correlation between the percentage of progressive motility spermatozoa and the ROS level in the seminal plasma in the two groups (r=−0.72, P<0.01).
Uncontrolled and excessive production of ROS is one of the major factors leading to an infertile status and causes oxidative stress, resulting in decreased sperm motility, viability, increased sperm capacitation, and acrosome reaction defects 17. This, in turn, can affect the fertilizing potential of germ cells 18. The destructive effect of oxidative stress on male gametes is mainly associated with the peroxidative processes of sperm membrane components and DNA fragmentation 19,20.
This study showed that ALA could work with its protective mechanisms (antioxidant and immune-modulator), enhancing the testicular function. According to previous studies with antioxidants, we expected an improvement mainly in sperm motility, but a surprising finding was the effect of the ALA on the count (P<0.001) after the third month of therapy; this could be related to the decrease in DNA fragmentation 21 and the hypothesized protective role of the germ cells 18. As most of the studies in the literature always attribute the increase in sperm count to either follicle-stimulating hormone or antiestrogens (clomiphene citrate and tamoxifen) 22, this study is the first to point out the role of ALA in improving sperm count in cases of idiopathic oligozoospermia.
Another theory that may explain the improvement in sperm count in our study is provided in the study of Gu et al. 23 of decreased activity of lactate dehydrogenase-x (LDH-x) with oxidative stress. LDH-x is a unique isoenzyme of lactate dehydrogenase in the inner mitochondrial membrane of the spermatogenic cells of mature and developing testis that is specific for germinal epithelium activity. The decreased activity of this enzyme represents a defect in spermatogenesis and testicular maturation. This explanation has been supported by the study of Verma et al. 24, who have reported a positive correlation between LDH-x activity and sperm count.
In this work, total and progressive motility of sperm showed improvement during the second and third months of therapy in the active group. The level of improvement was not statistically significant compared with the placebo group. In terms of the motility parameters studied by CASA in the active group, the three main types of motility improved (VCL, VSL, and VAP), but the most significant improvement was in VCL (P<0.001).
The improvement in motility is mainly because of its antioxidant action as the ability of ALA to create a robust shield on the cell membrane, along with the liquid that surrounds the sperm indirectly, enhances the ability of the sperm to tolerate higher volumes of free radical attack. This will, in turn, indirectly reduce the formation of deep pores and cracks on the sperm surface, thus ensuring structural integrity. The addition of ALA is believed to have aided the metabolism of oxidative decarboxylation by acting as a coenzyme 25. The increase in oxidative decarboxylation would increase the cytochrome C concentration and thus directly increase the mitochondria’s membrane potential, improving the regulation of mitochondria function and its biogenesis 26. In addition to the above, ALA has also been reported to aid the mitochondria’s citric cycle. This in turn will increase the level of reduced glutathione, ATP, and electron transport chain complex activities 27. ALA regulation of metabolism, increased availability of mitochondrial coenzymes, and improvement in the protection of free radicals are believed to eventually lead to a reduced incidence of mitochondria dysfunction, thus ensuring sufficient ATP for sperm movement 28.
Ibrahim et al. 11 reported that the sperm motility rate was improved after in-vitro incubation of semen samples with ALAs at a concentration of 0.02 mmol/ml. This concentration could also reduce DNA damage.
In our study, most of the patients in the active group who were able to impregnate their wives (four of five) showed increased count and motility starting from the second month of therapy. Thus, the improvement in both sperm count and motility may serve as a predictor for pregnancy in individuals receiving ALA therapy.
The limitations of this study are the limited number of participants, the fact that measurement of free radicals in semen was not carried out, and DNA fragmentation was not measured.
ALA may play a role in the treatment of idiopathic oligozoospermia. There was an increase in the pregnancy rate in the ALA group but a firm conclusion cannot be drawn from this finding because of the limited number of participants in this study. We recommend a future larger scale study with ALA in oligoathenozoospermia patients preferably on crossover bases to confirm our findings.
Conflicts of interest
There are no conflicts of interest.
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