Genetic Variants in Nitric Oxide Synthase Genes and the Risk of Male Infertility in a Chinese Population: A Case-Control Study

<div><p>Background</p><p>In recent years, oxidative stress has been studied extensively as a main contributing factor to male infertility. Nitric Oxide, a highly reactive free radical gas, is potentially detrimental to sperm function and sperm DNA integrity at high levels. Thus, the aim of this study was to investigate the associations between five polymorphisms in nitric oxide synthase genes (NOSs) and the risk of male infertility and sperm DNA damage as well.</p><p>Methods</p><p>Genotypes were determined by the OpenArray platform. Sperm DNA fragmentation was detected using the Tdt-mediated dUTP nick-end labeling assay, and the level of 8-hydroxydeoxyguanosine (8-OHdG) in sperm DNA was measured using immunofluorescence. The adjusted odds ratio (OR) and 95% confidence interval (CI) were estimated using unconditional logistic regression.</p><p>Results</p><p>Our results revealed a statistically significant difference between the cases and controls in both genotypic distribution (<i>P</i><0.001) and allelic frequency (<i>P</i> = 0.021) only for the <i>NOS3</i> rs1799983 SNP. Multivariate logistic regression analyses revealed that rs1799983 was associated with a borderline significantly increased risk of male infertility (GT vs. GG: adjusted OR = 1.30, 95% CI: 1.00–1.70; GT+TT vs. GG: adjusted OR = 1.34, 95% CI: 1.03–1.74; <i>P</i>_trend = 0.020). Moreover, <i>NOS3</i> rs1799983 was positively associated with higher levels of sperm DNA fragmentation (β = 0.223, <i>P</i> = 0.044). However, the other 4 polymorphisms (<i>NOS1</i> rs2682826, <i>NOS1</i> rs1047735, <i>NOS2</i> rs2297518, and <i>NOS2</i> rs10459953) were not found to have any apparent relationships with male infertility risk.</p><p>Conclusions</p><p>Of five <i>NOS</i> gene polymorphisms investigated in the present study, we found <i>NOS3</i> rs1799983 might cause oxidative sperm DNA damage, thereby contributing to male infertility.</p></div

SNPs information.

<p>Abbreviations: MAF, minor allele frequency; HWE, Hardy-Weinberg equilibrium.</p><p>*Minor allele frequency in the Chinese (CHB, Han Chinese in Beijing, China) population, as reported in dbSNP database.</p><p>SNPs information.</p

Box-and-whisker plots for sperm DNA damage levels in study subjects.

<p>The boxes represent the 25th and 75th percentiles; whiskers are lines extending from each end of the box covering the extent of the data on 1.5× inter-quartile range. The median value is denoted as the line that bisects the boxes. Circles represent the outlier values.</p

Distribution of selected characteristics between cases and fertile controls.

a<p>Among ever smokers.</p>b<p><i>P</i> values were derived from the χ² test for categorical variables (Age, BMI, smoking and drinking status) and t test for continuous variables (age, pack-years and BMI).</p><p>n. d.: not detected.</p><p>Distribution of selected characteristics between cases and fertile controls.</p

Effects of <i>NOS</i> SNPs on sperm DNA damage levels.

<p>Beta, regression coefficient; SE, standard error.</p>a<p>All analysis were done using linear regression models, adjusted for age, smoking status, drinking status and abstinence time.</p><p>Data in <i>boldface</i> represent <i>P</i><0.05.</p><p>Effects of <i>NOS</i> SNPs on sperm DNA damage levels.</p

Bithionol Restores Sensitivity of Multidrug-Resistant Gram-Negative Bacteria to Colistin with Antimicrobial and Anti-biofilm Effects

Being among the few last-resort antibiotics, colistin (COL) has been used to treat severe infectious diseases, such as those caused by multidrug-resistant Gram-negative bacteria (MDR GNB). However, the appearance of colistin-resistant (COL-R) GNB has been frequently reported. Therefore, novel antimicrobial strategies need to be urgently sought to address this resistance challenge. In the present study, antimicrobial drug screening conducted revealed that bithionol (BT), approved by the Food and Drug Administration and used as an anthelminthic drug for paragonimiasis, exhibited a synergistic antibacterial effect with COL. Clinically isolated COL-R GNB were used as candidates to evaluate the synergistic antibacterial activity. The results revealed that BT could significantly reverse the sensitivity of COL-R GNB to COL. Furthermore, the combined application of BT and COL can reduce bacterial biofilm formation and have a scavenging effect on the mature biofilm in vitro. The damage caused to the bacterial cell membrane integrity by the BT/COL combination was observed under a fluorescence microscope. The fluorescence intensity of reactive oxygen species also increased in the experimental group. The BT/COL combination also exhibited a synergistic antibacterial effect in vivo. Importantly, BT was confirmed to be safe at the highest concentrations that exerted synergistic effects on all tested strains. In conclusion, our findings demonstrated that BT exerted synergistic antimicrobial and anti-biofilm effects when combined with COL against MDR organisms, especially COL-R GNB, in vitro and in vivo. The findings thus provide a reference for the clinical response to the serious challenge of MDR GNB and the exploitation of the potential antibacterial activities of existing clinical non-antibacterial drugs

Differences in the distribution of <i>T</i>. <i>gondii</i> in different <i>muscle</i> and viscera of Small-tailed Han sheep.

Differences in the distribution of T. gondii in different muscle and viscera of Small-tailed Han sheep.</p

S1 File -

Toxoplasma gondii (T. gondii) is a zoonotic parasite that can cause serious pathology in intermediate hosts such as humans and animals. Eating undercooked or raw meat is the most important route of infection by T. gondii. Sheep are an important source of meat worldwide, and they are also susceptible to T. gondii. Mutton infected with T. gondii poses a serious threat to the food safety of consumers. At present, studies have mainly focused on the infection ratio of T. gondii in livestock; however, systematic studies have not been performed on differences in the distribution of this parasite in different muscle and viscera tissues of animals. In this study, the differences in the distribution of T. gondii in naturally infected Small-tailed Han sheep was studied. By amplifying the B1 gene of the parasite via real-time fluorescence quantification PCR (RT‒qPCR), we found that the parasite burden of T. gondii differed among different parts of the sheep, with the highest burden observed in the heart among the viscera and the external ridge among the muscle. The relative expression was ranked from high to low in our study as follows: heart, spleen, external ridge, tenderloin, lung, liver, kidney, neck meat, forelegs, cucumber strips, hind leg, lamb belly, and lamb chops. This study provided important guidance for monitoring the food safety of mutton products.</div

The ROS generation detection by DCFH-DA.

<p>(a) Effect of active oxygen scavengers on cell damage after SDT. To find out which one was the main inducer in apoptosis after SDT, several free radical scavengers such as 200 U/mL catalase (CAT, scavenger of hydrogen peroxide), 100 μg/mL superoxide dismutase (SOD, scavenger of superoxide anion radical), 100 mM mannitol (scavenger of hydroxyl radical) and 10 mM Sodium azide (NaN₃, scavenger of singlet oxygen) were employed before treatment. The cell viability was checked by the CCK-8 assay. Ultrasonically induced cell damage were significantly reduced in the presence of NaN₃ but not in the presence of CAT, SOD or mannitol, indicating singlet oxygen may be the main factor for cell damage. (b) Fluorescent photomicrograph of THP-1 macrophages stained by DCFH-DA showing intracellular ROS. (c) Intracellular ROS generation in THP-1 macrophages. ***p<0.001 <i>vs.</i> control. #p< 0.05 <i>vs.</i> SDT. Scale bar  =  0.1 mm.</p

The structure and physical optics characterization of Hydroxyl acetylated curcumin.

<p>(a) The structure of Hydroxyl acetylated curcumin (HAC). (b) The absorption spectrum of HAC. (c) The fluorescence emission spectrum of HAC.</p