STRUCTURE OF NEUROMUSCULAR JUNCTIONS AND DIFFERENTIATION OF STRIATED MUSCLE FIBERS OF MDX MICE AFTER BONE MARROW STEM CELLS
THERAPY
A. V. Sokolova,1 V. V. Zenin, V. M. Mikhailov
Institute of Cytology RAS, St. Petersburg;
1 e-mail: avsokolova@inbox.ru
Mdx mice are a model of Duchenne muscular dystrophy caused by deficiency of dystrophin. Muscles of
mdx mice are characterized by high levels of striated muscle fibers death and, accordingly, by a high level of its
regeneration. Moreover, the structure of neuromuscular junctions in mdx mice is altered. Changes in the structure
of mdx mice neuromuscular junctions against a background of increasing differentiation of striated muscle fibers
after C57BL/6 Lin (–) bone marrow stem cells transplantation were investigated. The muscles were studied
in 4, 8, 16 and 24 weeks after transplantation. We observed that the level of striated muscle fibers loss was decreased
from the 4th week after transplantation of bone marrow stem cells. Accumulation of muscle fibers without
centrally located nuclei began from the 8th week, and dystrophin synthesis was increased at the 16th and 24th
weeks after bone marrow stem cells transplantation. Longitudinal sections of quadriceps muscles of mdx mice
showed decrease in the number of acetylcholine receptors clusters in neuromuscular junctions and a simultaneous
increase in acetylcholine receptor clusters area during the 4th week after transplantation. In 16 weeks after
bone marrow stem cells transplantation, total neuromuscular junction area was increased due to increase in the
area of acetylcholine receptors clusters and to increase in their number as well. Thus, single intramuscular transplantation
of C57BL/6 Lin (–) bone marrow stem cells induces an increase in differentiation of mdx mice striated
muscle fibers and improves the structure of neuromuscular junctions.
Key words: mdx mice, cell therapy, neuromuscular junctions, Lin (–) bone marrow stem cells
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