THE HISTOPATHOLOGICAL CHANGE AND DYSTROPHIN
EXPRESSION IN THE MDX MICE BY BONE MARROW CELL TRANSPLANTATION |
C. Zhang*; W. Zhang; Z. Liu; X. Lu; X. Wang |
Dept Neurol, First Affiliated Hosp, Guangzhou, China |
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[Objective] To observe the histopathological change and
dystrophin expression in the mdx mice by bone marrow cell
transplantation.
[Methods] Different amounts of bone marrow cells, suspension cells and
stromal cells were cultured in vitro from C57BL male mice, and the
cells were transplanted intravenously into the 14 irradiated (8 Gy)
mdx mice . The survival rate and survival time were investigated. 1,
2, 3, and 4 months after transplantation, the muscle histopathological
analysis was assessed with immunofluorescent technique. Sex determined
region of the Y chromosome from the transplantation female mdx mice
were examined by means of PCR.
[Results] 3 months after transplantation, 10 mice were alive, and 4
mice died. A few dystrophin was observed in the mdx mice muscle about
1 or 2 months after transplantation. By 3 months after bone marrow
cells, suspension cells, and stromal cells transplantation, about 10
%, 8 % and 6 % of the muscle fiber expressed dystrophin respectively.
About 449 bp DNA fragments from Y chromosome were amplified in the
female mdx mice.
[Conclusion] This study shows that most mdx mice can survive by being
transplanted bone marrow cells, suspension cells, and stromal cells.
Dystrophin can be expressed by different component of marrow cell
transplantation, and the expression time of dystrophin can keep on at
least over three months.
Supported by the National Nature Science foundation of China
(39870804), Guangdong Nature Science foundation (970061)
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MANGANESE QUENCH RATES AND STEADY STATE CALCIUM CONCENTRATIONS IN CULTURED DYSTROPHIC MYOTUBES AND FRESHLY EXCISED ADULT DYSTROPHIC FIBERS.
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C.G. Carlson*; R. Ashmore; A. Gueorguiev; D. Roshek; J. Chu
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Dept. of Physiology, Kirksville College of Osteopathic Medicine, Kirksville, MO, USA |
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To examine the potential role of elevated intracellular [Ca] and enhanced resting Ca influx (RCI) in the pathogenesis of myopathies, steady state [Ca] was estimated from F340/F380 ratios and known [Ca] standards, and RCI was estimated from the rate of Mn quenching of intracellular signal in both FURA PE3 loaded spontaneously inactive cultured myotubes and freshly excised triangularis sterni (TS) muscle fibers. Initial studies indicated a significant effect of genotype on both F340/F380 ratios (p<0.05) and Mn quench rates (p<0.05), with utrophin-mdx double knockout (DKO) myotubes exhibiting a [Ca] (59.9 nM, 10.2SEM) that was about 68% larger than nondystrophic and 123% larger than mdx myotubes. In the presence of 100 microM ACh, both mdx and DKO myotubes had elevated Mn (1 mM) quench rates with DKO myotubes having rates (25.9 x 10(-4) sec(-1)) that were about 2.5 fold larger than mdx myotubes. Adult mdx TS muscle fibers, which are severely dystrophic, had significantly (p<0.001) elevated F340/F380 ratios and an estimated mean [Ca] of 218 nM in comparison to 113 nM in nondystrophic fibers. In the presence of Ca, the Mn (0.5 mM) quench rate in mdx TS fibers was elevated in comparison to nondystrophic fibers, but the difference failed to reach statistical significance (p>0.05). Quench rates (1.5 mM Mn) obtained in the absence of Ca were identical between nondystrophic and mdx TS fibers (2.2 x 10(-4) sec(-1)). These results are consistent with the general hypothesis that elevated steady state Ca concentrations promote the destruction of muscle fibers in myopathies. Supported by: an SRI award from KCOM.
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NEURONAL POTENTIAL OF STEM CELLS FROM
ADULT MUSCLE. |
M. Romero-Ramos1*; Y. Wu1;
R. Zaman1; P.A. Lucas2; H.E. Young3;
M.-F. Chesselet1 |
1. Dept of Neurology, UCLA School of Medicine,
Los Angeles, CA, USA |
2. Dept of Orthopedic Surgery, New York Medical
Collage, Valhalla, NY, USA |
3. Div of Basic Medical Science, Mercer
University School of Medicine, Macon, GA, USA |
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Stem cells have been identified within the
connective tissues of skeletal muscle (Lucas et al. 1995).
These cells can differentiate into multiple phenotypes of
the mesenchymal and other lineages (Lucas, Young,
unpublished observations), suggesting that they are
multipotent stem cells. It is unclear, however, whether
these cells could be induced to primarily express a neural
phenotype. We have isolated stem cells from adult rat muscle
and exposed them to growth factors and defined
differentiating conditions for 5 and 24 hours. Cells were
examined with immunocytochemistry and fluorescence assisted
cell sorting. At 5 hours, more than 90% of the cells
co-expressed phenotypic markers of mature neurons and glial
cells. This pattern of co-expression has been previously
shown in neuro-glial progenitors, suggesting that stem cells
from adult muscle can differentiate along a neuroectodermal
lineage. At 24 hours, most cells still expressed neuronal
markers whereas only a subset co-expressed glial markers.
Our study confirms the presence of multipotent stem cells in
adult muscle and shows that these cells are able to overcome
germ lineage restriction and express the characteristics of
neural stem cells. Therefore, stem cells isolated from adult
muscle could provide a novel source for autologous cell
replacement in neurodegenerative diseases.
Supported by: a BioStar Grant, P50-NS 38367, The Pasarow
Foundation and MorphoGen Pharmaceuticals, Inc.
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EFFECTS OF NEUROPEPTIDE Y (NPY) ON MUSCLE
PERFORMANCE AND FATIGABILITY IN RAT ISCHEMIC MUSCLES |
I. Kalezic1; E.W. Lee2;
M. Ljubisavlijevic1; H. Johansson1; Z.
Zukowska1,2* |
1. Centre for Musculoskeletal Research, NIWL,
Umea, Sweden |
2. Physiology & Biophysics, Georgetown Univ.,
Washington, DC, USA |
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Recently, Zukowskas
group has shown that NPY, a sympathetic neurotransmitter and
a vasoconstrictor, is angiogenic and induces
revascularization of the rat ischemic limb. Using this model,
we now studied the performance and fatigability of the
gastrocnemius muscle under isometric conditions at 14 days
after femoral artery occlusioninduced
ischemia and local administration of NPY (1mg/14 days/pellet,
IsN rats) or placebo (IsP), and compared to control
non-ischemic muscles (C). The gastrocnemius muscle was
unilaterally stimulated via the lateral and medial
gastrocnemius nerve or corresponding filaments isolated from
L5 and L6 ventral root using repetitive tetanic stimulation
(600 ms duration, 85 Hz fusion frequency, 1 sec intervals).
Series of increasing number of trains (1,3, 6, 12, 30 and
60, 60 sec intervals) were applied to each muscle. Current
intensity was 3-5 times the motor threshold in order to
evoke synchronous activation of all muscle fibers. During
trains 1-6, relative forces dropped faster in IsP than in
IsN and C muscles, while during trains 12-60, tension
diminished more in IsN and C. In IsP muscles, there was a
rapid, brief increase in tension followed by a quick drop to
1/3 of the peak value, which remained stable during the
whole train, as compared to C and IsN muscles where a fused
tetanus occured. These data suggest that NPY preserves the
ability of different fast-twitch fiber populations to
produce submaximal tetanic force in isometric condition, and
restores muscle performance and fatigability altered by
ischemia.
Supported by: Swedish Work Life Res. Council &
HL67357
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