There is a need for improved reproductive toxicology assays that do not require large numbers of animals but are sensitive and informative. Therefore, Staput velocity-sedimentation separation followed by culture of specific mouse testicular cells was used as such a system. The specificity of separation was assessed using immunocytochemistry to identify spermatids, spermatocytes and spermatogonia. The efficacy of the system to detect toxicity was then evaluated by analysing the effects of hydrogen peroxide (H2O2) by the terminal uridine-deoxynucleotide end-labelling (TUNEL) assay to show the rate of apoptosis induced among the different types of germ cells. We found that 2 h of treatment at both 1¿M and 10¿M induced increases of over ~10-fold in the percentage of apoptotic cells (p¿0.001), confirming that testicular germ cells are prone to apoptosis at very low concentrations of H2O2. It was also demonstrated for the first time for this compound that spermatogonia are significantly more susceptible than spermatocytes, which are more affected than spermatids. This reflects the proportion of actively dividing cells in these cell types, suggesting a mechanism for the differential sensitivity. The approach should thus form the basis of a useful test system for reproductive and genetic toxicology in the future.

<p>  </p> <p>Inhalation is a primary route of environmental and occupational exposures. Inhalation toxicology studies have thoroughly demonstrated the efficacy and adverse effects of a large number of chemicals, metals, pharmaceuticals, and agrochemicals. With the rapid development of new technologies and emergence of prominent subpopulations, some emerging exposure issues have arisen. To better protect public health, it is necessary to address these numerous emerging issues related to inhalation toxicology including 1) exposures to complex and unknown chemical emissions generated as we resolve infrastructure needs, 2) real-world exposure scenarios such as nanoparticle (NP) mixtures that may induce unique toxicity, and 3) variations in toxicity responses that occur in vulnerable and prevalent subpopulations following exposures. We designed three aims 1) to characterize differential representative composite manufacturing emissions (CMEs) and toxicity assessment of inhalation exposure to CMEs, 2) to examine the contribution of variable iron and manganese NP components in welding fumes to pulmonary toxicity, and 3) to evaluate metabolic syndrome (MetS)-induced variations in NP-Biocorona (NP-BC) composition following inhalation and modulation of pulmonary toxicity. Overall, this proposal aimed to characterize the emerging and complex exposures occurring in the real world and elucidate the mechanisms of differential pulmonary toxicity and susceptibility associated with CMEs, different metal NP components in welding fumes, and underlying diseases such as MetS. The conclusions from this project can help to improve the application of water infrastructure repairing technology and the utilization of welding and understand the mechanism of susceptibility to NP exposure among individuals with underlying diseases. Furthermore, the findings from these evaluations have supported and improved worldwide regulation, which promotes a safer utilization of novel materials, newly developed medicines, and complex chemicals.</p>