Evaluation of possible molecular toxicity induced by occupational exposure to lead and concomitant effect of smoking

Serum and Seminal Plasma Levels of Lead and Arsenic in Cigarette Smokers and Their Relation to the Semen Parameters

Male infertility along with altered semen parameters have been related to smoking. Smoking-related elevations in serum and seminal lead (Pb) and arsenic (As) may play a role in mediating the toxic effects of smoking on seminogram. This research aims to determine whether smoking has any significant impact on Pb and As levels in the seminal plasma and serum, as well as on the various semen parameters, when compared to nonsmokers. In total, 80 adult males were included: 60 smokers and 20 age-matched nonsmokers. Based on the number of cigarettes smoked/day (CPD), the smokers were categorized into mild (1-10), moderate (11-20), and severe (> 20). The analysis of semen was conducted in accordance with the 2010 WHO laboratory manual. Using an atomic absorption spectrophotometer, Pb and As concentrations in the serum and seminal plasma of all groups were determined. Compared to nonsmokers, smokers had a significantly reduced sperm count, motility, and viability, as well as a larger percentage of aberrant forms (P = 0.001, 0.025, 0.034, 0.002 respectively). Smokers had higher Pb concentrations in their serum and seminal fluid than nonsmokers (P = 0.002, 0.001 respectively). Seminal Pb had a significant negative correlation with sperm count (P = 0.004, r = -0.320). Serum Pb levels were found to positively correlate with seminal Pb levels (P 0.001, r = 0.648), and cigarette smokers had substantially greater seminal As levels than nonsmokers (P = 0.024). Sperm viability was strongly inversely related to seminal As (P = 0.042, r = -0.264). Seminal As levels and aberrant sperm shapes were found to be significantly correlated (P = 0.001, r = 0.414). In smokers, a significant positive relationship between seminal As and seminal Pb was observed. Therefore, semen parameters could be adversely affected by smoking through high levels of Pb and As (P = 0.012, r = 0.298).

Epidemiological characteristics of occupational chemical poisonings in Zhejiang, China from 2006 to 2020: A descriptive analysis

Objective

As the second most common occupational disease in China, occupational poisoning is one of the major public health problems that seriously affect workers' health. This study aimed to investigate the epidemiological and occupational characteristics of acute and chronic occupational poisoning cases in Zhejiang Province, so as to provide a scientific basis for proposing intervention measures and preventive strategies of occupational poisoning.

Methods

The data on occupational poisoning cases in Zhejiang Province from 2006 to 2020 was derived from the National Occupational Disease Network Direct Report System. A descriptive statistical analysis was employed on this data utilizing R software.

Results

From 2006 to 2020, 1,008 occupational poisoning cases were reported in Zhejiang Province, with a downward trend since 2007. Of these cases, 81.94% were chronic poisoning and 18.06% were acute poisoning. Ningbo reported the most occupational poisoning cases among the 11 cities in Zhejiang Province, accounting for 20.34% of the total cases. Besides, the occupational poisoning cases in Wenzhou, Jiaxing, and Shaoxing also accounted for 18.15%, 18.06%, and 17.76% of the total number of cases, respectively. Occupational poisoning in male were 693 cases and in female 315 cases. Most of the occupational poisoning cases studied involved people aged between 40 and 49 years (38.19%). The length of work in chronic occupational poisoning cases was significantly higher than that of acute occupational poisoning cases (P < 0.05). Benzene and lead and its compounds (excluding tetraethyl lead) were the major toxicants causing occupational poisoning. More than 60% of occupational poisoning cases were reported in private enterprises. Meanwhile, over 90% of the cases were distributed in medium enterprises and small enterprises. The type of industry with the most occupational poisoning cases was the manufacturing industry.

Conclusion

Although the cases of occupational poisoning in Zhejiang Province have declined, more comprehensive and effective prevention and control measures are still needed. More attention ought to be paid to the management of key points according to the epidemiological and occupational characteristics of occupational poisoning cases.

Protective effects of olive leaf extract against reproductive toxicity of the lead acetate in rats

Lead acetate (PbAc) is one of the toxic metals in the environment which causes many effects on different organs of the body. And due to the importance of the olive tree, with its healthy and protective elements against many diseases, the leaf extract of this tree was chosen in our study. Therefore, the aim of this study was to investigate the role of olive leaf (Olea europea L.) extract (OLE) against PbAc-induced sperm toxicity, sex hormone changes, oxidative stress, and histopathological changes in rats. Twenty male Wistar rats were divided into four groups (group 1, as control; group 2, OLE; group 3, PbAc; group 4, PbAc+OLE). In the PbAc group, the body weight, testis and epididymis weights, sexual hormones, sperm characteristics, GR, GPx, GST, GSH, SOD, and CAT were significantly decreased, and the sperm abnormality and TBARS level were significant increase when compared with control and OLE groups. Also, numerous damages to testicular tissue were observed in the PbAc group when compared to the control group, while the treatment with OLE in the fourth group led to improvement of sex hormones, semen characteristics, oxidative stress, and testicular tissue damage caused by PbAc. It can be concluded that OLE has a protective and ameliorative effects against PbAc-induced oxidative stress, apoptosis and alterations in testicular tissue, and sperm quality in rats.

Plant Polyphenols: Potential Antidotes for Lead Exposure

Lead is one of the most common heavy metal elements and has high biological toxicity. Long-term lead exposure will induce the contamination of animal feed, water, and food, which can cause chronic lead poisoning including nephrotoxicity, hepatotoxicity, neurotoxicity, and reproductive toxicity in humans and animals. In the past few decades, lead has caused widespread concern because of its significant threat to health. A large number of in vitro and animal experiments have shown that oxidative stress plays a key role in lead toxicity, and endoplasmic reticulum (ER) stress and the mitochondrial apoptosis pathway can also be induced by lead toxicity. Therefore, plant polyphenols have attracted attention, with their advantages of being natural antioxidants and having low toxicity. Plant polyphenols can resist lead toxicity by chelating lead with their special chemical molecular structure. In addition, scavenging active oxygen and improving the level of antioxidant enzymes, anti-inflammatory, and anti-apoptosis are also the key to relieving lead poisoning by plant polyphenols. Various plant polyphenols have been suggested to be useful in alleviating lead toxicity in animals and humans and are believed to have good application prospects.

Influence of VDR and HFE polymorphisms on blood lead levels of occupationally exposed workers

Lead is a ubiquitous heavy metal toxin of significant public health concern. Every individual varies in their response to lead's toxic effects due to underlying genetic variations in lead metabolizing enzymes or proteins distributed in the population. Earlier studies, including our lab, have attributed the influence of ALAD (δ-Aminolevulinate dehydratase) polymorphism on blood lead retention and ALAD activity. The present study aimed to investigate the influence of VDR (Vitamin D receptor) and HFE (Hemochromatosis) polymorphisms in modulating blood lead levels (BLLs) of occupationally exposed workers. 164 lead-exposed subjects involved in lead alloy manufacturing and battery breaking and recycling processes and 160 unexposed controls with BLLs below 10 µg/dL recruited in the study. Blood lead levels, along with a battery of biochemical assays and genotyping, were performed. Regression analysis revealed a negative influence of BLLs on ALAD activity (p < 0.0001) and a positive influence on smokeless tobacco use (p < 0.001) in lead-exposed subjects. A predicted haplotype of the three VDR polymorphisms computed from genotyping data revealed that T-A-A haplotype increased the BLLs by 0.93 units (p ≤ 0.05) and C-C-A haplotype decreased the BLLs by 7.25 units (p ≤ 0.05). Further analysis revealed that the wild-type CC genotype of HFE H63D presented a higher median BLL, indicating that variant C allele may have a role in increasing the concentration of lead. Hence, the polymorphism of genes associated with lead metabolism might aid in predicting genetic predisposition to lead and its associated effects.

Redox Status, Dose and Antioxidant Intake in Healthcare Workers Occupationally Exposed to Ionizing Radiation

The purpose of this study was to evaluate the relationship between blood redox status, dose and antioxidant dietary intake of different hospital staff groups exposed to low doses of ionizing radiation (LDIR) (Interventional Radiology and Cardiology, Radiation Oncology, and Nuclear Medicine) and non-exposed. Personal dose equivalent (from last year and cumulative), plasma antioxidant markers (total antioxidant capacity, extracellular superoxide dismutase activity, and glutathione/oxidized glutathione ratio), oxidative stress markers (nitrites and nitrates, and lipid peroxidation) and dietary intake (antioxidant capacity using ORAC values) were collected and analyzed from 28 non-exposed healthcare workers and 42 healthcare workers exposed to LDIR. Hospital staff exposed to LDIR presented a redox imbalance in blood that seems to correlate with dose. Workers from the Nuclear Medicine Unit were the most affected group with the lowest value of plasma antioxidant response and the highest value of plasma thiobarbituric acid reactive substances, TBARS (indicator of lipid peroxidation) of all four groups. Cumulative personal dose equivalent positively correlated with nitrites and negatively correlated with total antioxidant capacity in blood. The diet of healthcare workers from Nuclear Medicine Unit had higher ORAC values than the diet of non-exposed. Therefore, occupational exposure to LDIR, especially for the Nuclear Medicine Unit, seems to produce an imbalanced redox status in blood that would correlate with cumulative personal dose equivalent.