ГЕНЕТИКА, 2012, том 48, № 3, с. 405-407
КРАТКИЕ СООБЩЕНИЯ
УДК 575.1:599.9
NO ASSOCIATION BETWEEN THE G196A AND C270T POLYMORPHISM OF THE BRAIN-DERIVED NEUROTROPHIC FACTOR GENE
AND MALE INFERTILITY © 2012 г. *Ch. Li1, *L. Zheng2, Y. Sun1, 3, Ch. Wang1, 4, W. Li1, Ch. Lu1, X. Zhou1
1 College of Animal Science and Veterinary Medicine, and Jilin Provincial Key Laboratory of Animal Embryo Engineering, Jilin University, Changchun, Jilin Province, 130062 China e-mail: xzhou65@vip.sina.com 2 The Second Hospital of Jilin University, Reproductive Medical Center, Changchun, Jilin Province, 130062 China 3 College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118 China 4 Liaoning Medical University, Jinzhou, Liaoning Province, 121001 China Received May 05, 2011
Brain-derived neurotrophic factor (BDNF) plays important roles in neuronal development and reproductive action. Abnormal expression of BDNF gene has been detected in human sperm and seminal serum. In the present study, we investigated the possible association of G196A and C270T polymorphism of BDNF gene with male infertility. The genotypes of the G196A and C270T polymorphisms were in Hardy-Weinberg equilibrium both in fertile and infertile group. The genotype distribution frequencies were similar between infertile and fertile group. The results showed that the G196A and C270T polymorphism of the BDNF gene is unrelated to the male infertility, at least in a Chinese population.
Brain-derived neurotrophic factor (BDNF) is a member of the nerve growth factor family. The biological action of BDNF is mainly mediated by its receptor (protein tyrosine kinase B, TrkB). The human BDNF gene is mapped in chromosome 11p13 [1]. It has been found that BDNF play an important role in promoting neuronal survival, differentiation and neuroprotection [2]. Several polymorphisms of BDNF have been reported and studied in neuronal illnesses, including Val66Met polymorphism (-196G/A) [3], the -270C/T substitution [4], the -374A/T, and the 256G/A polymorphisms [5].
Recently, growing evidence has suggested the important roles of BDNF in the development of a variety of non-neuronal tissues, including reproductive systems [6, 7]. Previous studies have shown that ovarian BDNF promotes both oocyte maturation, by enhancing first polar body extrusion, and the in vitro development of zygotes into preimplantation embryos through its TrkB receptor [8]. BDNF has been detected in adult Legdig and Stertoli cells using immunocy-tochemistry, while its high affinity receptor, TrkB has been found in spermatogonia [9], indicating that BDNF could have a potential role in testis development. In our recent studies, BDNF and TrkB transcripts and proteins were detected in human and bovine mature sperm [10, 11]. In bovine, BDNF could regulate the secretion of insulin and leptin, and affect the mito-chondrial activity, apoptosis, and viability of sperm [10]. Abnormal expression of BDNF mRNA in human
* Indicates these authors are co-first author.
sperm and BDNF protein in seminal plasma existed, indicating that BDNF gene might be associated with the pathogenesis of some cases of male infertility [11].
To our knowledge, there are no reports of any association between male infertility and BDNF polymorphism. The aim of the present study was to examine the possible association between BDNF polymorphisms G196A and C270T and male infertility. The 272 male subjects who participated in this study were recruited randomly from the Reproductive Medical Center of the Second Hospital affiliated of Jilin University. Mean age was 32.3 years old. The semen was obtained by masturbation after 3 days of sexual abstinence and allowed to liquefy for 30 min at 38.5°C before processing. Semen analysis was performed according to the World Health Organization (1999) guidelines. Of the 272 samples analyzed, 163 were as-thenozoospermic (<25% rapid motility or <50% progression in a semen sample, and fresh sperm concentration >20 x 106/ml), 47 oligoasthenozoospermic (motility <25%, and fresh sperm concentration <20 x x 106/ml), and 62 fertile male subjects (>25% rapid motility or >50% progression in a semen sample, and fresh sperm concentration >20 x 106/ml) (Table 1). Written informed consent was obtained from all the patients and controls induced in this study. The study was approved by the national medical ethics committee.
Purification of genomic DNA from the human sperm was performed using standard kit procedures (TIANGEN, Beijin, China). Two pairs of primers were designed to detect BDNF G196A (Forward:ATC-
406 LI et al.
Table 1. Data of studied groups
Samples (N) Volume, ml Density, million/ml Motility, %
Asthenozoospermia (163) 2.9 ± 0.2 75.5 ± 7.9 28.3 ± 2.7
Oligoasthenozoospermia (47) 2.7 ± 0.1 8.8 ± 0.6 22.0 ± 3.3
Fertile (62) 3.1 ± 0.1 82.6 ± 7.1 68.8 ± 3.1
Table 2. Distribution of genotypes, N(%), for BDNFG196A and C270T in fertile and infertile subjects
Samples G196A 2 X2 P C270T 2 X2 P
A/A A/G G/G C/C C/T T/T
C 10 (16.1) 33 (53.2) 19 (30.6) 58 (96.7) 2 (3.3) 0 (0)
A 29 (17.8) 77 (47.2) 57 (35) x2 = 0.65, P = 0.72 147(93) 11 (7) 0 (0) x2 = 0.48, p = 0.49
O 13 (27.7) 21 (44.6) 13 (27.7) X2 = 2.2, p = 0.34 43 (97.7) 1 (2.3) 0 (0) x2 = 0, p = 1
Note: C = control (fertile group); A = asthenozoospermia group; O = oligoasthenozoospermia group.
CGAGGACAAGGTGGC; Reverse :CCTCATGGA-CATGTTTGCAG) and C270T (Forward:CAGAG-GAGCCAGCCCGGTGCG; Reverse:CTCCTG-CACCAAGCCCCATTC) polymorphisms. Polymerase chain reaction (PCR) was carried out in a final volume of 25 |l containing 100 ng DNA, 2.5 |l of 10xBuffer, 0.2 |M of each primer, 0.20 units of rTaq polymerase (TaKaRa Biotechnology). The amplification products were purified by ethanol precipitation kit (TIANGEN, Beijin, China) and digested with 10 units of Pml (G196A) and Hinfl (C270T) at 37°C overnight. The resulting DNA fragments for G196A polymorphism were electrophoresed on a 2% agarose gel and visualized using ethidium bromide. The digested DNA for C270T were separated on a 8% polyacrylamide gel and visualized with ethidium bromide staining.
The presence of Hardy—Weinberg equilibrium for the genotypic distribution was tested by using the x2 test for goodness-of-fit. Genotype and allele frequencies between patients and control subjects were compared by Pearson's chi-squared test. A P-value < 0.05 was considered statistically significant. Odds ratio (OR) and 95% confidence interval (95% CI) were used to express the relative risk. Calculations were performed using the program SPSS version 13.0.
The results of this study showed that the genotypes of the G196A and C270T polymorphisms were in Hardy—Weinberg equilibrium in fertile, asthenozoosper-mic, and oligoasthenozoospermic group (P > 0.05). Genotype distributions of the G196A and C270T polymorphisms in the asthenozoospermic, oligoast-henozoospermic, and control fertile group were shown in Table 2. There were no significant differences in the genotype distribution between infertile (as-thenozoospermic, oligoasthenozoospermic) and the control fertile group.
The analysis of polymorphisms in genes involved in spermatogenesis is an exciting method to study male
infertility in genetics. Genetic variants in these genes are considered potential risks factors which may cause the severity of male infertility. Until now, several polymorphic variants have been studied in association with male infertility, for example, polymorphisms of androgen receptor exon 1 [12], 5-methylenetetrahydro-folate reductase (MTHFR) [13], FSHR [14], and estrogen receptor (ER) a [15], et al. The BDNF gene is an attractive candidate gene that might be associated with some neural illnesses. It is well known that BDNF G196A is associated with BDNF secretion from neuronal cells. In our previous study, BDNF level in sperm and seminal plasma is abnormal [10]. To further investigate whether the abnormal expression of BDNF is caused by mutation of BDNF gene, we analyzed the genotype of BDNF in fertile and infertile group to evaluate the association of BDNF polymorphism with male infertility.
After analyzing our data, there were no significant difference in genotype and allele of G196A and C270T between fertile and infertile group. The results suggested that G196A and C270T polymorphisms of BDNF gene were not major contributing factor infertility. The phenotypic effects of gene polymorphisms are modulated by other genetic factors and environmental factors [16]. The specific population and population size are the major factors to study association between gene polymorphism and disease. In summary, the study did not provide the association of G196A and C270T polymorphisms of BDNF gene with male infertility. Further studies should be needed to investigate the other variants of the BDNF gene using different populations and larger populations.
rEHETHKA TOM 48 № 3 2012
NO ASSOCIATION BETWEEN THE G196A AND C270T POLYMORPHISM
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ACKNOWLEDGMENT
This work was supported by the Science and Technology Development Project of Changchun City (08GH08).
REFERENCES
1. Maisonpierre, P.C., Le Beau, M.M., Espinosa, R., 3rd., et al., Human and rat brain-derived neurotrophic factor and neurotrophin-3: gene structures, distributions, and chromosomal localizations, Genomics., 1991, vol. 10, no. 3, pp. 558-568.
2. Hashimoto, K., Shimizu, E., Iyo, M., Critical role of brainderived neurotrophic factor in mood disorders, Brain Res. Rev., 2004, vol. 45, no. 2, pp. 104-114.
3. Cargill, M., Altshuler, D., Ireland, J., et al., Characterization of single-nucleotide polymorphisms in coding regions of human genes, Nat. Genet., 1999, vol. 22, no. 3, pp. 231-238.
4. Kunugi, H., Ueki, A., Otsuka, M., et al., A novel polymorphism of the brain-derived neurotrophic factor (BDNF) gene associated with late-onset Alzheimer's disease, Mol. Psychiatry, 2001, vol. 6, no. 1, pp. 83-86.
5. Ribases, M., Gratacos, M., Armengol, L., et al., Met66 in the brai
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