Pulmonary exposure to carbonaceous nanomaterials and sperm quality

Abstract

BackgroundSemen quality parameters are potentially affected by nanomaterials in several ways: Inhaled nanosized particles are potent inducers of pulmonary inflammation, leading to the release of inflammatory mediators. Small amounts of particles may translocate from the lungs into the lung capillaries, enter the systemic circulation and ultimately reach the testes. Both the inflammatory response and the particles may induce oxidative stress which can directly affect spermatogenesis. Furthermore, spermatogenesis may be indirectly affected by changes in the hormonal milieu as systemic inflammation is a potential modulator of endocrine function. The aim of this study was to investigate the effects of pulmonary exposure to carbonaceous nanomaterials on sperm quality parameters in an experimental mouse model.MethodsEffects on sperm quality after pulmonary inflammation induced by carbonaceous nanomaterials were investigated by intratracheally instilling sexually mature male NMRI mice with four different carbonaceous nanomaterials dispersed in nanopure water: graphene oxide (18 μg/mouse/i.t.), Flammruss 101, Printex 90 and SRM1650b (0.1 mg/mouse/i.t. each) weekly for seven consecutive weeks. Pulmonary inflammation was determined by differential cell count in bronchoalveolar lavage fluid. Epididymal sperm concentration and motility were measured by computer-assisted sperm analysis. Epididymal sperm viability and morphological abnormalities were assessed manually using Hoechst 33,342/PI flourescent and Spermac staining, respectively. Epididymal sperm were assessed with regard to sperm DNA integrity (damage). Daily sperm production was measured in the testis, and testosterone levels were measured in blood plasma by ELISA.ResultsNeutrophil numbers in the bronchoalveolar fluid showed sustained inflammatory response in the nanoparticle-exposed groups one week after the last instillation. No significant changes in epididymal sperm parameters, daily sperm production or plasma testosterone levels were found.ConclusionDespite the sustained pulmonary inflammatory response, an eight week exposure to graphene oxide, Flammruss 101, Printex 90 and the diesel particle SRM1650b in the present study did not appear to affect semen parameters, daily sperm production or testosterone concentration in male NMRI mice.Electronic supplementary materialThe online version of this article (10.1186/s12989-018-0242-8) contains supplementary material, which is available to authorized users.

Occupational exposure to graphene based nanomaterials: risk assessment

“…In addition, reproductive toxicity data after the usual occupational exposure routes should be implemented, although no adverse effects were observed after repeated intratracheal instillations (one exposure per week for 7 consecutive weeks) of GO in NMRI male mice. 19 Similarly, no reproductive adverse effects were observed in ICR male mice after single intravenous (6.25-25 mg kg −1 ) or 5 days of intraperitoneal injection (up to 60 mg kg −1 day −1 ) of small GO or large GO. 45 No effects were recorded after the intravenous injection of small rGO or large rGO to ICR male and female 6-8 week-old mice (6.25-25.0 mg kg −1 ).…”

“…The increased neutrophil number in the broncho-alveolar lavage fluid suggested pulmonary inflammation. 19 In conclusion, these few studies after intratracheal instillation suggest the lung as the target organ and the storage depot of GBMs, with the following toxicity rank: FLG < GNP < rGO < GO. Different pieces of evidence of lung inflammation and fibrosis were observed both after acute exposure and after one exposure per week for 7 consecutive weeks.…”

“…No significant changes in epididymal sperm parameters, daily sperm production or tes-tosterone levels were found after GO exposure, suggesting no reproductive toxicity in male mice. 19…”

Inhalation of welding fumes reduced sperm counts and high fat diet reduced testosterone levels; differential effects in Sprague Dawley and Brown Norway rats

“…The cellular inflammatory response in the lung following airway exposure to nanosized particles is often characterized by PMN influx to the bronchoalveolar space which correlates with induction of inflammatory cytokines [39]. Inflammatory mediators released to the blood may be transported to extra pulmonary organs and have been hypothesized to exert adverse effects on the testes and interfere with spermatogenesis in an indirect way [17,35]. Here, we measured serum levels of TNFa, IL-6, CRP, and CCL2/ MCP-1 in the Sprague Dawley rats.…”

“…The daily sperm production (DSP) was calculated using the formula DSP = N / 6.10, where N is the total number of spermatids per sample calculated using a standard counting chamber formula and 6.10 represents the number of days for a spermatid to develop through stages 14 to 16 in rats, i.e. the stages where spermatids are resistant to homogenization [35]. Sperm content per gram of testes (SC/G testes ) was calculated by dividing total sperm counts with the testicular weight.…”