Skeletal muscle abnormalities associated with occupational exposure to mercury vapours

• Published in: Histology and histopathology Vol. 15; no. 3; p. 673
• Main Authors: Nadorfy-López, E, Torres, S H, Finol, H, Méndez, M, Bello, B
• Format: Journal Article
• Language: English
• Published: Spain 01.07.2000
• Subjects: Adult; Air Pollutants, Occupational - adverse effects; Air Pollutants, Occupational - urine; Dental Technicians; Dentists; Female; Humans; Mercury - adverse effects; Mercury - urine; Middle Aged; Muscle Fibers, Skeletal - classification; Muscle Fibers, Skeletal - pathology; Muscle, Skeletal - blood supply; Muscle, Skeletal - pathology; Occupational Exposure - adverse effects
• ISSN: 0213-3911
• DOI: 10.14670/HH-15.673

There is scarce information on the possible effects of chronic exposure to mercury on skeletal muscle. Dental personnel are frequently exposed to inhalation of metallic mercury vapours. The skeletal muscle of five technicians and one dentist (females, age 36-55) was studied. All of them presented symptoms of chronic mercury poisoning. Needle biopsy was taken from the quadriceps femoris muscle and samples were prepared for light microscope histochemistry and for transmission electron microscopy. Selective atrophy of type IIB muscle fibres was found in patients, and in one of them there was fibre grouping. Most of the muscles showed increased fibre area per capillary. Atrophy was confirmed by the ultrastructural study, demonstrating increase of intermyofibrillar spaces, loss of myofibrils or complete disappearance in some fibres, and sarcolemmal foldings. Splitting of the fibres was also found. Some capillaries were altered, showing endothelial infoldings into the lumen, thickened basement membrane and partial or total occlusion. The alterations found in muscle may be secondary to nerve damage, to ischemia caused by capillary lesion and/or to a direct effect of mercury on muscle fibre proteins.