Effects of inhaled methyl methacrylate monomers from acrylic prostheses on mouse lung tissue

Introduction: Materials based on polymethyl methacrylate (PMMA) have become more widely used because of their many benefits in various medical specialties, such as maxillofacial surgery, ophthalmology, and orthopedic prostheses. Since methyl methacrylate (MMA), the monomer from which PMMA is made, is extremely volatile and breathed during handling, inhalation is the main way that laboratory and healthcare workers are exposed to MMA. This compound is toxic and can irritate the respiratory mucosa, respiratory system, skin, nervous system, and other organs. Objective: This study aims to assess the effect of MMA inhalation on lung tissue histology. Methods: This in vivo experimental study used 15 white mice, which were randomly assigned to three groups: A negative control, a group exposed to MMA for 1 week, and a group exposed for 3 weeks. Mice were subjected to MMA inhalation for 6 h/day. Following exposure, lung tissues were processed for histological examination, including fixation, dehydration, paraffin embedding, sectioning, and hematoxylin-eosin staining. Lung injury was evaluated using a semi-quantitative histological scoring system and by measuring alveolar diameter in five fields of view. Results: No lung damage was observed in the control group; lung histology remained within normal limits. The group exposed to MMA for 1 week showed mild to moderate lung damage, whereas the group exposed for 3 weeks exhibited moderate to severe histological damage. Measurements of alveolar diameter showed a decrease in both MMA-exposed groups. Conclusion: Inhalation exposure to MMA causes significant histological damage to lung tissue in mice.