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Objective To study the relationship of urinary total arsenic exposure level with sperm quality and sex hormone levels in young male population, and evaluate the potential impact of background arsenic exposure on parameters of sperm quality and sex hormone levels in Chongqing. Methods Generalized additive model and recursive algorithm were used to analyze the correlation of the baseline urine arsenic concentration with semen parameters and sex hormone levels in 703 male college students volunteers (18~22 years old) in the cohort of Chongqing college students constructed in 2013-2015. The inflection point of the nonlinear relationship was explored, and the threshold effect of arsenic exposure was analyzed. The median of urinary arsenic in this study was compared with the data from other reports at home and abroad. Results There was a nonlinear relationship of urine arsenic level with sperm concentration, sperm total number, sperm DNA fragment index, and levels of prolactin, follicle-stimulating hormone and progesterone. Further threshold effect analysis showed that there were inflection points of urine arsenic concentration with the above indicators, and the key points were 15.17, 14.17, 50.97, 57.51, 11.36, and 70.44 μg/L, respectively (Log-likelihood ratio test P < 0.05). Compared with relevant literature, the urine arsenic level was at a relatively lower level in this cohort population. Conclusion Compared with some regions at home and abroad, the background urine arsenic level of this study population is quite lower, and significant correlation is found in the background level with the decline of sperm quality parameters and changes in sex hormone levels.

Objective To establish a damage model of mouse spermatocyte GC-2spd cells induced by benzo[k] fluoranthene (BkF), a representative compound of high-molecular weight polycyclic aromatic hydrocarbons, so as to investigate the effect and mechanism of BkF on GC-2 cells. Methods Related genes of male reproductive diseases associated with BkF were screened in Comparative Toxicogenomics Database (CTD), and functional and pathway enrichment analysis is conducted subsequently to explore the possible pathway mechanism. Moreover, GC-2 cells were treated with BkF at a final concentration of 0, 10, 20, 40 or 80 μmol/L for 72 h, and then the cell cycle, oxidative stress and DNA damage effect were detected. Western blotting was used to determine the protein levels of the key genes as well as the core molecules of related pathways. Results The key genes CYP1A1 and CYP17A1 associated with BkF-related reproductive system diseases were screened out from the CTD database. Gene Ontology (GO) enrichment analysis found that they were involved in male reproductive system and cell cycle arrest, obviously enriched in biological processes such as oxidative stress. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that these genes were significantly enriched in cytochrome P450 pathway (P < 0.01). After GC-2 cells were exposed to BkF for 72 h, the proliferation was significantly decreased in a dose-dependent manner, as compared with the control group. When the exposure dose was higher than 40 μmol/L, the cell cycle arrest was obvious (P < 0.05); Both the intracellular reactive oxygen species (ROS) level (P < 0.05) and the protein level of DNA damage marker γ-H2AX (P < 0.01) were remarkably increased in a dose-dependent manner. In addition, the protein levels of CYP1A1 and CYP17A1 were greatly higher in the exposure group than the control group (P < 0.05), while treatment of AhR inhibitor CH223191 resulted in notably down-regulated the expression of the 2 proteins (P < 0.05). Conclusion BkF induces the activation of AhR receptors, then causes elevated expression of downstream genes CYP1A1 and CYP17A1 as well as increased intracellular ROS, and finally leads to oxidative stress and genetic damage in GC-2 cells.

Objective To investigate the association of the ratio of second to fourth digit with adult male reproductive phenotypes in the undergraduates in Chongqing. Methods A total of 569 male undergraduates were sampled from our previously established cohort of the male reproductive health in Chongqing college students(MARHCS) study. Their lengths of second and fourth digits in the left hand were measured to calculate the ratio of second to fourth digit. And their anogenital distance, testicular vertical diameters, testicular volume, semen parameters and reproductive hormone levels were measured and detected. Results The median digit ratio was 0.97 in the subjects, with 86.29% of them having the ratio ≤1. After adjustment of smoking, drinking, body mass index and abstinence period, a 0.1 increase of digit ratio was associated with 12.5%(95%CI: 0.7%~37.3%, P=0.033) increase of semen volume, and 87.1%(95%CI: 1.3%~819.9%, P=0.038) increase of total sperm count. Single factor variance analysis showed that the digit ratio was significantly correlated with the distance of anus center to scrotum posterior base(AS) in (r=0.136, P=0.001). When the covariates were controlled, a 0.1 increase of digit ratio was associated with 2.5%(95%CI: 0.3%~5.2%, P=0.023) increase of the anogenital distance. Compared to the subjects with digit ratio ≤1, those with digit ratio>1 were associated with -10.3%(95%CI: -17.6%~-2.5%, P=0.012) follicle-stimulating hormone. However, these associations were not statistical significance after multiple-test correction. Conclusion Conclusion Digit ratio has no substantial association with adult reproductive phenotypes, including semen parameters and reproductive hormones in the healthy male college students in Chongqing.

Objective To analyze the relationship between air pollutants and spontaneous abortion in Chongqing. Methods Time trend bias was controlled by time-stratified case-crossover design. The distribution lag nonlinear model was employed to study the relationship between air pollution and the number of spontaneous abortion in the main urban area of Chongqing and to control the influence of confounding factors such as meteorological factors. Based on the single pollutant model, the two-pollutant model was used to control the influence of other pollutants on correlation. Results During the study period, the average daily concentration of PM2.5, PM10, NO2 and SO2 in the air was 39.32, 63.31, 41.04 and 8.86μg/m3, respectively. All pollutants except NO2 were associated with the risk of spontaneous abortion, and all the associations reached the peak value at the lag of 3 d. For the increase of every 10μg/m3, the relative risk value was 1.069 (95%CI: 1.010~1.132), 1.046 (95%CI: 1.007~1.086) and 1.511 (95%CI: 1.148~1.989), respectively. These associations still existed in the two-pollutants model. Conclusion Short-term exposure of PM2.5, PM10 and SO2 in the ambient air may increase the risk of spontaneous abortion in Chongqing.

Objective To investigate the association between exposure to polycyclic aromatic hydrocarbons(PAHs) in atmospheric fine particulate matter(PM2.5) and sperm DNA damage in Chongqing. Methods The subjects were sampled from our previously established cohort of the male reproductive health in Chongqing college students(MARHCS) study. The concentrations of PAHs(collected during the sampling periods) with low fused aromatic rings(2~4 rings) and with high fused aromatic rings(5~6 rings) in the air PM2.5 filter membranes were detected. Single cell gel electrophoresis(Comet assay) was used to evaluate DNA damage. Finally, the mixed-effects model was used to investigate the relationships between the exposure concentrations of PAHs components in PM2.5 and severity of sperm DNA damage. Results In 2013, the low molecular weight(LMW) PAHs accounted for a large proportion in atmospheric fine particles, mainly phenanthrene, fluorene and pyrene. While, the high molecular weight(HMW) PAHs dominated in 2014, such as indeno[1, 2, 3-cd]pyrene, benzo[g, h, i]perylene and benzo[a]pyrene. Sperm DNA damage indicators, such as tail length, tail moment and Olive tail moment were more common in the cohort in the year of 2014 than in 2013(all P < 0.05). The results of the mixed model showed that the concentrations of fluoranthene, acenaphthene, pyrene and ∑LMW PAHs were negatively correlated with tail length and tail moment. The concentrations of benzo[k]fluoranthene, benzo[b]fluoranthene and dibenz[a, h]anthracene were positively correlated with tail length [β(95%CI): 108.987(43.754~203.820), 158.700(65.957~303.272), 185.708(67.350~387.775), respectively; all corrected P < 0.05] and with tail moment [β(95%CI): 449.204(260.066~737.695), 683.108(374.515~1192.387), 683.108(374.515~1 192.387), respectively; all corrected P < 0.05]. Conclusion The exposure of HMW PAHs in Chongqing atmospheric fine particles may lead to the enhancement of sperm DNA damage.

Objective To explore the expression pattern of cannabinoid receptor 1 (CBR1) in reproductive toxicity induced by dibutyl phthalate (DBP) exposure in male rats, and investigate the underlying mechanism. Methods Sixty healthy male Sprague-Dawley rats were randomly divided into 4 groups (15 animals in each group), that is, control group, and low-, medium- and high-dose groups, exposure to 100, 250 and 500 mg/kg DBP, respectively, by intragastric injection daily for 28 consecutive days. Computer-aided sperm analysis system (CASA) was used to detect sperm vitality, concentration, and rate of deformity. HE staining was employed to observe the changes in testicular tissue. The serum levels of testosterone (T), estradiol (E2), luteinizing hormone (LH), follicle stimulating hormone (FSH) and sex hormone binding protein (SHBG) were measured by ELISA. The expression of p38, ERK, AKT and CBR1 at mRNA and protein levels was measured by RT-PCR and Western blotting. Results Compared with the control rats, the sperm motility and total sperm motility were reduced in low- (20.1±9.2 and 73.6±3.2), middle- (22.3±6.2 and 40.7±24.4) and high-dose (21.0±14.2 and 41.2±4.6) exposure groups (P < 0.05). Sperm concentration was significantly lower in the high-dose group (152.0±67.0, P < 0.05). Compared with the control group, serum T levels were significantly lower in the middle- (19.65±2.65) and high-dose groups (17.40±3.50, both P < 0.05). The serum level of E2 was significantly decreased in each exposure group (2.09±0.08, 2.11±0.77, 2.05±0.02) when compared to the control group. So were the serum LH levels (7.80±1.42, 7.68±2.28, 6.43±0.90) (all P < 0.05). While the serum level of FSH was all significantly increased in each exposure group (2.88±0.37, 2.89±0.29, 3.37±0.30), when compared to the control group (P < 0.05). In the testis tissue, the expression of CBR1 was increased at mRNA and protein levels than that of the control group, and the expression of p-p38 and p-ERK was significantly decreased than the control group (P < 0.05). Conclusion DBP exposure results in impairment of testicular tissue structure and decrease of sperm motility in male rats, which may be due to the up-regulation of CBR1 and the subsequent inhibition of ERK/p38MAPK phosphorylation.

Emerging research findings suggest that airborne particulate matter might be a risk factor for gestational diabetes mellitus (GDM). However, the concentration–response relationships and the susceptible time windows for different types of particulate matter may vary. In this retrospective analysis, we employ a novel robust approach to assess the crucial time windows regarding the prevalence of GDM and to distinguish the susceptibility of three GDM subtypes to air pollution exposure. This study included 16,303 pregnant women who received routine antenatal care in 2018–2021 at the Maternal and Child Health Hospital in Chongqing, China. In total, 2482 women (15.2%) were diagnosed with GDM. We assessed the individual daily average exposure to air pollution, including PM2.5, PM10, O3, NO2, SO2, and CO based on the volunteers' addresses. We used high-accuracy gridded air pollution data generated by machine learning models to assess particulate matter per maternal exposure levels. We further analyzed the association of pre-pregnancy, early, and mid-pregnancy exposure to environmental pollutants using a generalized additive model (GAM) and distributed lag nonlinear models (DLNMs) to analyze the association between exposure at specific gestational weeks and the risk of GDM. We observed that, during the first trimester, per IQR increases for PM10 and PM2.5 exposure were associated with increased GDM risk (PM10: OR = 1.19, 95%CI: 1.07~1.33; PM2.5: OR = 1.32, 95%CI: 1.15~1.50) and isolated post-load hyperglycemia (GDM-IPH) risk (PM10: OR = 1.23, 95%CI: 1.09~1.39; PM2.5: OR = 1.38, 95%CI: 1.18~1.61). Second-trimester O3 exposure was positively correlated with the associated risk of GDM, while pre-pregnancy and first-trimester exposure was negatively associated with the risk of GDM-IPH. Exposure to SO2 in the second trimester was negatively associated with the risk of GDM-IPH. However, there were no observed associations between NO2 and CO exposure and the risk of GDM and its subgroups. Our results suggest that maternal exposure to particulate matter during early pregnancy and exposure to O3 in the second trimester might increase the risk of GDM, and GDM-IPH is the susceptible GDM subtype to airborne particulate matter exposure. [ABSTRACT FROM AUTHOR]