Apoptosis and apoptosis-related proteins in thyroid myopathies.
DNA fragmentation and apoptosis-related proteins have been investigated in thyroid cells and there is evidence that Fas-mediated apoptosis is inhibited by thyroid stimulating hormone (TSH). We investigated DNA fragmentation by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), and Bcl-2 and Fas antigen expression by immunocytochemistry in skeletal muscles from 12 patients with hypothyroid myopathy and 5 patients with hyperthyroid myopathy. The finding of very few TUNEL-positive muscle fibers in both conditions suggests that apoptosis does not play a role in the pathogenesis of thyroid myopathies. Bcl-2 expression increased significantly in hypothyroid myopathy, correlating with high serum TSH levels, and not with either triiodothyronine (T3) or thyroxine (T4) serum levels. By contrast, Fas antigen was overexpressed in hyperthyroid myopathy, correlating with low TSH levels. These findings suggest an anti-apoptotic role for TSH itself in skeletal muscle.
Monici
Maria C
MC
Clinica Neurologia 2, Department of Neurosciences, Psychiatry and Anaesthesiology, Policlinico Universitario, 98125 Messina, Italy.
Rodolico
Carmelo
C
Toscano
Antonio
A
Messina
Sonia
S
Benvenga
Salvatore
S
Messina
Corrado
C
Vita
Giuseppe
G
D000293:Adolescent; D000328:Adult; D000368:Aged; D017209:Apoptosis; D001706:Biopsy; D005260:Female; D006801:Humans; D020287:In Situ Nick-End Labeling; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000737:chemistry / Q000473:pathology*; D009133:Muscular Atrophy / Q000209:etiology / Q000473:pathology; D009135:Muscular Diseases / Q000209:etiology / Q000473:pathology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis; D013959:Thyroid Diseases / Q000097:blood / Q000150:complications / Q000473:pathology*; D013972:Thyrotropin / Q000097:blood; D019014:fas Receptor / Q000032:analysis
D019253:Proto-Oncogene Proteins c-bcl-2; D019014:fas Receptor; D013972:Thyrotropin