Impairment of sperm efficiency in mice following short-term nano-titanium dioxide exposure: An experimental study.

BACKGROUND: Titanium dioxide nanoparticles (TiO 2 NPs) are widely used in many compounds. Recent evidence has displayed some cytotoxic effects of TiO 2 NPs on male reproduction. OBJECTIVE: The effects of TiO 2 NP administration on sperm parameters and chromatin and seminiferous histopathology of male mice were investigated. MATERIALS AND METHODS: In this experimental study, 32 NMRI male mice (35 ± 3 gr, 8-12-week-old) were divided into four groups (n = 8/each): treated groups were fed orally with 2.5 (group I), 5 (group II) and 10 (group III) mg/kg/day TiO 2 NPs for 40 days and the control group received phosphate buffered saline. Sperm parameters, DNA integrity and chromatin quality were assessed using chromomycin A3, aniline blue, toluidine blue staining and TUNEL. Hematoxylin eosin staining was performed to measure spermatogenic cells and the total diameter of seminiferous tubules. Also, sex hormone and malondyaldehyde levels were measured. RESULTS: Abnormal sperm tails rose in group III (28.87 ± 4.91) in comparison with the control group (12.75 ± 3.95). However, chromomycin A3 staining and TUNEL showed higher levels in group III in comparison with the control group, whereas aniline blue and toluidine blue staining showed no differences. A significantly lower spermatogenesis index and lumen parameters were observed in group III. Leydig cell numbers, cellular diameters and the area of the seminiferous tubules were lower in the treated groups. The testosterone level was also lower in these groups and the percentage of malondyaldehyde in the seminal fluid was higher. CONCLUSION: Exact mechanisms of TiO 2 NPs are not clear; however, cytotoxic and genotoxic effects of TiO 2 NPs may relate to oxidative stress. Given their widespread use, TiO 2 NPs should be a public health focus of attention.

Toxic effects of maternal exposure to silver nanoparticles on mice fetal development during pregnancy.

BACKGROUND: Silver nanoparticles (SNPs) are being increasingly used in medical and industrial products. The aim of the present study was to evaluate the toxic effect of maternal exposure to SNP (1 mg/kg/day, 70 nm) on fetal development during the first and second weeks of pregnancy. METHODS: Twenty-four pregnant mice were divided into four groups. SNP was administered by oral gavage on gestational days (GD) 1-7, GD8-14, or GD1-14. Phosphate buffered saline was administered by oral gavage to a control group. On GD15, the uteri were excised, and fetal bodies and placentas were weighed. Head and placental circumferences and fetal crown-rump length were measured, and fetuses were evaluated for external malformation. TUNEL assay was performed to assess apoptosis in the fetal midbrain. Hematoxylin-eosin staining was carried out to determine changes in fetal histomorphology. Fetal liver cells were used for karyotype analysis. RESULTS: Significant decreases in fetal body weight, and crown-rump length were observed in SNP-treated groups. Exencephaly, small head, scoliosis, lordosis, short thorax and trunk, also fused digits were detected in SNPs-treated groups. Fibrosis, necrosis, and apoptotic cells in fetal midbrains increased significantly in the GD8-14 and GD1-14 groups compared to the control group. Chromosomal features were not different in fetuses between groups. CONCLUSIONS: Exposure to 1 mg/kg/day SNP during pregnancy in mice adversely affected on fetal development. The results do suggest a potential risk for humans that needs to be followed up with more definitive investigations.

The association between TNP2 gene polymorphisms and Iranian infertile men with varicocele: A case-control study.

BACKGROUND: Numerous researches have provided great evidence that revealed the relationship between varicocele and sperm DNA damage. OBJECTIVE: Because of the crucial role of nuclear transition proteins (TPs) in sperm DNA condensation and integrity, this case-control study was designed to study TNP2 gene nucleotide variations in Iranian patients with varicocele. MATERIALS AND METHODS: PCR-SSCP and DNA sequencing were used to search for mutations in exons 1 & 2 of the TNP2 gene in 156 infertile patients with varicocele and 150 fertile men. RESULTS: The results of sequencing showed three variants at positions c.301C░>░T (p.R101C), c.391C░>░T (p.R131░W), and g.IVS1-26G░>░C (rs8043625) of TNP2 gene. It was found that varicocele risk in men who have the CC genotype of g.IVS1-26G░>░C SNP is higher than those who don't have these genotypes (according to Co-dominant model, Dominant model, Recessive model, and Over-dominant model). The haplotype-based analysis showed that (C/C/T) and (C/T/T) haplotypes were a risk factor of in patients with varicocele compared to controls (OR░=░3.278, p░=░0.000 and OR░=░9.304, p░=░0.038, respectively). CONCLUSION: Because of the significant difference in the genotype and allele frequencies of g.IVS1-26G░>░C SNP in the intronic region of TNP2 in patients with varicocele compared with controls and also because of the high conservation of this SNP position during evolution, this SNP may be involved in some important processes associated with the expression of this gene like mRNA splicing, but the exact mechanism is not clear.

Mitochondrial Genetic Variation in Iranian Infertile Men with Varicocele.

BACKGROUND: Several recent studies have shown that mitochondrial DNA mutations lead to major disabilities and premature death in carriers. More than 150 mutations in human mitochondrial DNA (mtDNA) genes have been associated with a wide spectrum of disorders. Varicocele, one of the causes of infertility in men wherein abnormal inflexion and distension of veins of the pampiniform plexus is observed within spermatic cord, can increase reactive oxygen species (ROS) production in semen and cause oxidative stress and sperm dysfunction in patients. Given that mitochondria are the source of ROS production in cells, the aim of this study was to scan nine mitochondrial genes (MT-COX2, MT-tRNALys , MT-ATP8, MT-ATP6, MT-COX3, MT-tRNAGly , MT-ND3, MT-tRNAArg and MT-ND4L) for mutations in infertile patients with varicocele. MATERIALS AND METHODS: In this cross-sectional study, polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and DNA sequencing were used to detect and identify point mutations respectively in 9 mitochondrial genes in 72 infertile men with varicocele and 159 fertile men. In brief, the samples showing altered electrophoretic patterns of DNA in the SSCP gel were sent for DNA sequencing to identify the exact nucleotide variation. RESULTS: Ten type nucleotide variants were detected exclusively in mitochondrial DNA of infertile men. These include six novel nucleotide changes and four variants previously reported for other disorders. CONCLUSION: Mutations in mitochondrial genes may affect respiratory complexes in combination with environmental risk factors. Therefore these nucleotide variants probably lead to impaired ATP synthesis and mitochondrial function ultimately interfering with sperm motility and infertility.

Effect of prenatal methamphetamine administration during gestational days on mice.

BACKGROUND: Methamphetamine (MA) is one of most common illicit drugs which were reported that nearly half of MA consumers are women. MA can cross through placenta and affects pregnancy and fetus development. OBJECTIVE: Our aim was to evaluate effects of injected MA on crown-rump length, head and placental circumference, body weight, histological changes and apoptosis in fetus. MATERIALS AND METHODS: Twenty-four NMRI pregnant mice were randomly divided into five groups. First, second and third groups were injected intraperitoneally 10 mg/kg/day MA during gestational days (GD): GD1-7, GD8-14, and GD1-14, respectively. Forth group, as sham, was injected saline from GD1-14, and finally control which was received neither MA nor saline. On GD15 cervical dislocated pregnant mice, fetus and placenta were weighed and fetus crown-rump length was measured. Hematoxylin and Eosin staining and TUNEL assay were applied to assess histological changes and apoptosis respectively. RESULTS: Fetus body weight and crown-rump length showed significant decrease in third compared to first and second groups (p≤0.001). There were significant differences in head circumference in control and sham compared to third group (0.5 (0.5-0.6), 0.6 (0.5-0.8), 0.4 (0.4-0.5) cm respectively, p≤0.001). Also fetus that treated with MA showed lower placenta circumference compared to control and sham groups. Histological changes such as exencephaly, hemorrhage and immature fetus were observed in second and third groups. Apoptotic cells in second and third groups were higher than controls, but differences were not significant. CONCLUSION: It seems MA abuse during pregnancy can cause morphological and histological changes in mice fetus but the exact mechanism remains unclear.