Formaldehyde inhalation during pregnancy abolishes the development of acute innate inflammation in offspring

Prenatal Origins of Obstructive Airway Disease: Starting on the Wrong Trajectory?

From the results of well-performed population health studies, we now have excellent data demonstrating that deficits in adult lung function may be present early in life, possibly as a result of developmental disorders, incurring a lifelong risk of obstructive airway diseases such as asthma and chronic obstructive pulmonary disease. Suboptimal fetal development results in intrauterine growth restriction and low birth weight at term (an outcome distinct from preterm complications), which are associated with subsequent obstructive disease. Numerous prenatal exposures and disorders compromise fetal development and these are summarized herein. Various physiological, structural, and mechanical abnormalities may result from prenatal disruption, including changes to airway smooth muscle structure-function, goblet cell biology, airway stiffness, geometry of the bronchial tree, lung parenchymal structure and mechanics, respiratory skeletal muscle contraction, and pulmonary inflammation. The literature therefore supports the need for early life intervention to prevent or correct growth defects, which may include simple nutritional or antioxidant therapy. © 2024 American Physiological Society. Compr Physiol 14:5729-5762, 2024.

Effect of fish oil supplementation on histological changes, apoptosis and oxidative stress of rat placenta against formaldehyde-induced toxicity

Formaldehyde (FA) as a common organic compound has been shown to cause placental dysfunction and fetal defects. The potential benefits of fish oil (FOil) in protecting placental structures are attributed to its antioxidant properties. This study aimed to explore the preventive role of FOil in mitigating the adverse effects of FA in pregnant rats. Thirty pregnant Wistar rats were randomly categorized into five groups of control, sham (Normal saline; Orally and intraperitoneally), FOil (0.5 ml/day; Orally), FA (5 mg/kg/bw; intraperitoneally), FA+FOil. The treatment period was from day 0-20 of pregnancy. On the 20th day of pregnancy, placental morphometric parameters were measured. The histological and histochemical analyses were performed using H&E and PAS staining, respectively. Also, the placenta tissue was analyzed for oxidative stress biomarkers, p-53 protein levels, and the expression of caspase-3 gene. The administration of FA led to a significant decrease in the weight, diameter, and thickness of the placenta, as well as a decrease in the thickness of the decidua layer, junctional and labyrinth zone, and the number of trophoblast giant cells in rat placentas. FA led to a significant increase in placental p-53 protein levels, caspase-3 expression, and oxidative stress biomarkers. Administration of FOil to pregnant rats treated with FA led to a significant decrease in morphometric and histological changes, oxidative stress, and the expression of genes associated with apoptosis. The findings suggest that the administration of FOil to FA-treated pregnant rats can protect placental histopathological changes by enhancing the activity of the antioxidant enzymes.

Repeated saline injections reduce the pulmonary allergic inflammatory response in rats by inducing short-term stress

Purpose

Asthma is characterized by pulmonary cell infiltration and hyper-responsiveness of the airways. Short-term stress reduces airway inflammation. Thus, in the present study, we examined the effects of short-term stress induced by repeated treatment with saline injections on the pulmonary allergic inflammatory response in rats.

Methods

Adult male rats were divided into three groups: Naïve group (non-sensitized, challenged, or treated rats), Control group (rats sensitized with ovalbumin (OVA) to induce lung inflammation), and Saline group (rats treated for five days with saline before OVA sensitization). Inhalation challenges were performed one week after the booster with aerosolized OVA. On day 18, the effect of saline injections on total and differential leukocytes in bronchoalveolar lavage (BAL), femoral marrow lavage (FML), and blood was evaluated. The percentage of mucus, serum corticosterone, collagen, cytokines in lung explants, and norepinephrine levels were also measured.

Results

OVA sensitization increased the circulating leukocytes and their migration to the lung, decreasing the bone marrow leukocytes. The repeated saline injections prevented this migration by decreasing the number of leukocytes in BAL and blood in the control group. Cytokine Interleukin-4 (IL-4) was higher in the control group than in the naive and saline groups; cytokines Interleukin-6 (IL-6), Interleukin-10 (IL-10), and tumor necrosis factor-alpha (TNFα) were higher in the control and saline groups than in the naïve group; Interferon gamma (IFNγ) was higher in the saline group than in the naive and control groups; norepinephrine increased in animals sensitized with OVA and was higher only in the saline group relative to the naïve group.

Conclusions

These results suggest that short-term stress could contribute to the anti-allergic airway inflammation effects of a given treatment.

Long-term exposure to formaldehyde induced down-regulation of SPO11 in rats

Objective: Formaldehyde, a ubiquitous environmental contaminant, has long been suspected of causing male reproductive injury, but the underlying molecular mechanism remains largely unknown. SPO11 is a meiosis-related gene, whose absence can cause spermatogenesis arrest. Materials and methods: The present study aimed to explore the role of SPO11 in male reproductive injury induced by long-term formaldehyde exposure, so as to further understand the molecular mechanism of formaldehyde-induced male reproductive toxicity. Adult male Sprague-Dawley rats (n = 24, 245 ± 22 g) were randomly divided into four groups of six (n = 6) and were exposed to formaldehyde gas at doses of 0 (control), 0.5, 2.46 and 5 mg/m³, respectively, via inhalation for 8 consecutive weeks. Results and dissussion: The expression levels of SPO11 were detected in testicular tissues by real-time quantitative polymerase chain reaction, immunofluorescence, and Western blot. The results indicated that the expression of SPO11 was inhibited by formaldehyde exposure in a dose-dependent manner. Furthermore, the histopathological results showed that testicular seminiferous tubules were atrophied, spermatogenic cells were decreased and the lumina were oligozoospermic in the 2.46 and 5 mg/m³ formaldehyde exposure groups. Combined with the morphometric results, we found that the downregulated expression levels of SPO11 were consistent with the changes of testicular seminiferous tubule diameter and seminiferous epithelium height in testicular tissue, suggesting that SPO11 might be one of the main targets of formaldehyde reproductive toxicity. Conclusions: In conclusion, our findings indicated that SPO11 might be related to male reproductive injuries induced by long-term formaldehyde exposure.

Prenatal programming of the immune response induced by maternal periodontitis: Effects on the development of acute lung injury in rat pups

AIMS

Oral cavity pathogens play an important systemic role, modulating the development of several diseases. Periodontitis is a very common oral disease associated with dental biofilm. It is characterized by gum inflammation, periodontal ligament degeneration, dental cementum and alveolar bone loss. Studies point to the association between maternal periodontitis and adverse outcomes during pregnancy. However, they did not evaluate the impact of maternal periodontitis in the offspring. Thus, our objective was to investigate the effects of maternal periodontitis in the immune system of offspring.

MATERIAL AND METHODS

For this evaluation we induced acute lung injury in rat pups. Pregnant rats were submitted or not to periodontitis by ligature technique. Thirty days after the birth, offspring was submitted to acute lung inflammation by administration of lipopolysaccharide (LPS, Salmonella abortus equi, 5 mg/kg, ip).

KEY FINDINGS

Our results showed that maternal periodontitis increased myeloperoxidase activity, the levels of TNF-alpha and IL-17A in the bronchoalveolar fluid, the gene expression of TNF-alpha, IL-17A, and cyclooxygenases 1 and 2. In addition, maternal periodontitis did not alter the number of leukocytes migrated into the lung, tracheal responsiveness, expression of TLR4 and NF-KB translocation.

SIGNIFICANCE

This study showed prenatal programming of the immune response induced by maternal periodontitis, and reinforces the importance of oral health care during pregnancy.

Effect of systemic photobiomodulation in the course of acute lung injury in rats

Acute lung injury (ALI) is a severe, multifactorial lung pathology characterized by diffuse alveolar injury, inflammatory cell infiltration, alveolar epithelial barrier rupture, alveolar edema, and impaired pulmonary gas exchange, with a high rate of mortality; and sepsis is its most common cause. The mechanisms underlying ALI due to systemic inflammation were investigated experimentally by systemic lipopolysaccharide (LPS) administration. Photobiomodulation (PBM) has been showing good results for several inflammatory diseases, but there are not enough studies to support the real benefits of its use, especially systemically. Considering that ALI is a pathology with high morbidity and mortality, we studied the effect of systemic PBM with red light-emitting diode (LED) (wavelength 660 nm; potency 100 mW; energy density 5 J/cm; total energy 15 J; time 150 s) in the management of inflammatory parameters of this disease. For this, 54 male Wistar rats were submitted to ALI by LPS injection (IP) and treated or not with PBM systemically in the tail 2 and 6 h after LPS injection. Data were analyzed by one-way ANOVA followed by Student's Newman-Keuls. Our results point to the beneficial effects of systemic PBM on the LPS-induced ALI, as it reduced the number of neutrophils recruited into the bronchoalveolar lavage, myeloperoxidase activity, and also reduced interleukins (IL) 1β, IL-6, and IL-17 in the lung. Even considering the promising results, we highlight the importance of further studies to understand the mechanisms involved, and especially the dosimetry, so that in near future, we can apply this knowledge in clinical practice.

Formaldehyde toxicity reports from in vitro and in vivo studies: a review and updated data

Formaldehyde (FA) is a xenobiotic air pollutant and its universal distribution causes a widespread exposure to humans. This review aimed to bring updated information concerning FA toxicity in humans and animals based on in vitro and in vivo studies from 2013 to 2019. Researches were carried out in Pubmed, Scopus, and Science Direct databases to determine the effects of FA exposure on inflammation, oxidative stress and genotoxicity in experimental studies with animals (rats and mice) and humans. Besides, in vitro studies assessing FA cytotoxicity focusing on cell viability and apoptosis in different cell line cultures were reviewed. Studies with humans gave evidence regarding significant deleterious effects on health associated to chronic FA occupational exposure. Evaluations carried out in experimental studies showed toxic effects on different organs as lung, upper respiratory tract, bone marrow and brain as well as in cells. In summary, this study demonstrates that knowing the mechanisms underlying FA toxicity is essential to understand the deleterious effects that this xenobiotic causes on biological systems.

The impact of maternal periodontitis in the development of asthma in the offspring

Clinical and experimental studies show an association between maternal periodontitis and adverse outcomes during gestation. On the other hand, there were no studies evaluating the impact of maternal periodontitis on the offspring. Thus, our objective was to investigate the repercussion of maternal periodontitis on the development of asthma in the offspring. Pregnant rats were submitted or not to periodontitis by ligature technique. Thirty days after birth, the puppies were sensitized and challenged with ovalbumin (OVA) in order to induce asthmatic response. Our results showed that maternal periodontitis reduced cellular infiltrate in the parenchyma of offspring, tracheal responsiveness, lung edema, and anti-OVA antibodies, without alter mucus as well as cytokines production. We concluded that periodontitis has relevant impact on the offspring's immune system, blunting the response to allergic and inflammatory stimulus. This study shows the important role of oral health during pregnancy and opens possibilities for future studies in order to explain the effects of periodontitis during pregnancy in the offspring.

Effects of formaldehyde exposure on the development of pulmonary fibrosis induced by bleomycin in mice

Environmental and Occupational pollution has been extensively studied because of its serious implications on the human health. Formaldehyde (FA) is a pollutant widely employed in several industries and also in anatomy, pathology and histology laboratories. Studies have shown the correlation between FA exposure and development or worsening of asthma. However, the effect of FA exposure on the pulmonary fibrosis (PF) is unknown. PF is a progressive and chronic lung disease with high incidence and considerable morbidity and mortality. Few studies have shown a worsening of PF after pollutants exposure such as ozone and nitrogen dioxide. Therefore, our objective was to assess the effects of FA on the PF. Male mice C57BL6 were treated or not with bleomycin (1,5 U/kg) and exposed or not to FA inhalation (0.92 mg/m3, 1 h/day, 5 days/week during 2 weeks). Non-manipulated mice were used as control. Our data showed that FA exposure in fibrotic mice increased the number of granulocytes in the bronchoalveolar lavage followed by elevated levels of interleukin 1 beta and interleukin 17. In addition, FA exposure in fibrotic mice enhanced the gene expression of C-X-C motif chemokine ligand 1 (CXCL1) and tumor necrosis factor alpha (TNF-α) in the lung. We also showed an increase in the collagen production, while lung elastance was reduced. No differences were found in the mucus production, oedema and interstitial thickening in the lung tissue of fibrotic mice after FA exposure. In conclusion our study showed that FA exposure aggravates the lung neutrophils influx and collagen production, but did not alter the lung elastance, mucus production, oedema and interstitial tickening. This work contributes to understand the effects of pollution in the development of PF.

Beneficial effects of Red Light-Emitting Diode treatment in experimental model of acute lung injury induced by sepsis

Sepsis is a severe disease with a high mortality index and it is responsible for the development of acute lung injury (ALI). We evaluated the effects of light-emitting diode (LED) on ALI induced by sepsis. Balb-c mice were injected with lipopolysaccharide or saline and then irradiated or not with red LED on their tracheas and lungs for 150 s, 2 and 6 h after LPS injections. The parameters were investigated 24 h after the LPS injections. Red LED treatment reduced neutrophil influx and the levels of interleukins 1β, 17 A and, tumor necrosis factor-α; in addition to enhanced levels of interferon γ in the bronchoalveolar fluid. Moreover, red LED treatment enhanced the RNAm levels of IL-10 and IFN-γ. It also partially reduced the elevated oxidative burst and enhanced apoptosis, but it did not alter the translocation of nuclear factor κB, the expression of toll-like receptor 4 (TLR4), as well as, oedema or mucus production in their lung tissues. Together, our data has shown the beneficial effects of short treatment with LED on ALI that are caused by gram negative bacterial infections. It is suggested that LED applications are an inexpensive and non-invasive additional treatment for sepsis.

Vitamin E Reversed Apoptosis of Cardiomyocytes Induced by Exposure to High Dose Formaldehyde During Mice Pregnancy

In this study, we investigated the protection effect of Vitamin E (Vit E) on formaldehyde (FA) exposure during pregnancy induced apoptosis of cardiomyocytes, and used an HL-1 cell line to confirmed the findings in vivo.Pregnant mice received different doses of FA (0.5 mg/kg, 1.0 mg/kg, 1.5 mg/kg, 0.1 μg Vit E, or 1.5 mg/kg + 0.1 μg Vit E). TUNEL staining was used to reveal the apoptosis in cardiomyocytes, and SOD, MDA, GSH, Livin, and Caspase-3 in cardiomyocytes were detected by ELISA, RT-PCR, and Western blot. For in vitro study, HL-1 cells were treated with vehicle, 5 μmol/L FA, 25 μmol/L FA, 50 μmol/L FA, 10 mg/L Vit. E, and 50 μmol/L FA+ 10 mg/L Vit E, respectively. CCK-8 assay and flow cytometry were used to evaluate cell vitality and apoptosis. A high dose of FA exposure led to cytotoxicity in both pregnant mice and offspring, as TUNEL staining revealed a significant apoptosis of cardiomyocytes, and the alternation in SOD, GSH, MDA, Livin, and Caspase-3 was found in cardiomyocytes. 0.1 μg Vit. E could reverse high doses of FA exposure induced apoptosis of cardiomyocytes in both pregnant mice and offspring. The in vitro study revealed that FA exposure induced a decrease of cell viability and increased cell apoptosis, as well as oxidative stress in HL-1 cells with alternation in SOD, GSH, MDA, Livin, and Caspase-3.This study revealed a high dose of FA induced oxidative stress and apoptosis of cardiomyocytes in both pregnant mice and offspring, and Vit E supplement during pregnancy reversed the systemic and myocardial toxicity of FA.

Common cold among pre-school children in China - associations with ambient PM10 and dampness, mould, cats, dogs, rats and cockroaches in the home environment

BACKGROUND

There is some evidence that dampness, mould and cockroaches can increase the risk of respiratory infections in children but few studies exist from China on this topic. Aim To study associations between domestic early life exposure to biological indoor factors (dampness, mould, cats, dogs, rats, cockroaches), cleaning habits and common cold among pre-school children across China.

METHODS

Children aged 3-6years (n=39,782) were recruited from randomly selected day care centres in seven cities in China. Data on common cold and prenatal and postnatal exposure to dampness, mould, windowpane condensation in wintertime (WPC), cats, dogs, cockroaches and rats were assessed by a parentally administered questionnaire. Data on annual ambient temperature and PM₁₀ was assessed on city level. Associations between high frequency (>5 colds per year) and long duration (≥2weeks) of common colds in the past year and exposure were calculated by multilevel logistic regression.

RESULTS

A total of 9.2% had a high frequency and 11.9% had long duration of common cold. Exposure to mould (OR=1.38, 95% CI 1.24-1.53) and WPC (OR 1.23, 95%CI 1.13-1.33) at birth was associated with frequent common cold. Exposure to dogs at birth was associated with long duration of common cold. (OR=1.22, 95% CI 1.06-1.41). Exposure to mould (OR=1.36, 95% CI 1.22-1.54), WPC (OR=1.27, 95%CI 1.17-1.39) and water leakage (OR 1.34, 95% CI 1.20-1.49) in the current home was associated with frequent common cold. Presence of cockroaches were positively (OR=1.12, 95% CI 1.02-1.24) and presence of rats (OR=0.86, 95% CI 0.77-0.96) negatively associated with high frequency of common cold. Daily cleaning was negatively associated with frequent common cold (OR=0.89, 95% CI 0.81-0.97). Similar associations for mould, WPC, cockroaches and rats were found for long duration. Ambient PM₁₀ (OR=1.21, 95% CI 1.21-1.35 per 10μg/m³) and temperature (OR=1.13, 95% CI 1.06-1.35 °C) on city level were associated with high frequency of common cold. Associations between cat keeping and high frequency of common cold were found only in southern China. Associations with cockroaches were stronger in northern China. Associations with dampness and mould were the same in the north and south.

CONCLUSIONS

Indoor mould, water damage, windowpane condensation, cockroaches and keeping cats or dogs as pets can be risk factors for common cold while daily cleaning can be protective factor. PM₁₀ and a warmer climate zone can be other risk factors for common cold.

Recent advances in green nanoparticulate systems for drug delivery: efficient delivery and safety concern

Nanotechnology manipulates therapeutic agents at the nanoscale for the development of nanomedicines. However, there are current concerns over nanomedicines, mainly related to the possible toxicity of nanomaterials used for health medications. Due to their small size, they can enter the human body more readily than larger sized particles. Green chemistry encompasses the green synthesis of drug-loaded nanoparticles by reducing the use of hazardous materials in the synthesis process, thus reducing the adverse health impacts of pharmaceutics. This would greatly expand their potential in biomedical treatments. This review highlights the potential risks of nanomedicine formulations to health, delivery routes of green nanomedicines, recent advances in the development of green nanoscale systems for biomedical applications and future perspectives for the green development of nanomedicines.

Photobiomodulation Therapy Decreases Oxidative Stress in the Lung Tissue after Formaldehyde Exposure: Role of Oxidant/Antioxidant Enzymes

Formaldehyde is ubiquitous pollutant that induces oxidative stress in the lung. Several lung diseases have been associated with oxidative stress and their control is necessary. Photobiomodulation therapy (PBMT) has been highlighted as a promissory treatment, but its mechanisms need to be better investigated. Our objective was to evaluate the effects of PBMT on the oxidative stress generated by FA exposure. Male Wistar rats were submitted to FA exposure of 1% or vehicle (3 days) and treated or not with PBMT (1 and 5 h after each FA exposure). Rats treated only with laser were used as control. Twenty-four hours after the last FA exposure, we analyzed the effects of PBMT on the generation of nitrites and hydrogen peroxide, oxidative burst, glutathione reductase, peroxidase, S-transferase enzyme activities, the gene expression of nitric oxide, cyclooxygenase, superoxide dismutase, the catalase enzyme, and heme oxygenase-1. PBMT reduced the generation of nitrites and hydrogen peroxide and increased oxidative burst in the lung cells. A decreased level of oxidant enzymes was observed which were concomitantly related to an increased level of antioxidants. This study provides new information about the antioxidant mechanisms of PBMT in the lung and might constitute an important tool for lung disease treatment.

High dose of formaldehyde exposure during pregnancy increases neutrophils lung influx evoked by ovalbumin in the offspring

OBJECTIVE

Considering that asthma might have their onset in the intrauterine life and the exposure to FA during pregnancy interferes in the immune system of offspring, here we hypothesized that high dose of FA exposure during pregnancy could to contribute for development and severity of asthma in the offspring.

METHODS

Pregnant Wistar rats were submitted to FA inhalation (6.13 mg/m(3), 1 h/day, 5 days/week, for 21 days) or vehicle (distillated water). After 30 days of birth, the offspring was sensitized with ovalbumin (OVA)-alum and challenged with aerosolized OVA (1%, 15 min, 3 days). After 24 h the OVA challenge, the analyses were performed. Non-manipulated rats were used as basal parameters.

RESULTS

Our data show that the exposure to high dose of FA during pregnancy predisposes the development of neutrophilic lung inflammation in the offspring, as observed by the profile of cells and cytokines in the lung.

CONCLUSION

This study contributes to the understanding of effects of pollution on the development of lung diseases.