A major focus of more basic work seeks to use various models to better assess the impact of disease on muscle health and function and improved methods for assessing the impact of therapies. One advantage of performing animal studies is our ability to assess a variety of therapies to see how they impact muscle and outcome measures. We have studied a number of therapies in our work, including immunomodulatory therapies, myostatin inhibitors, thyroid modulating drugs, and drugs that effect ion channel function. We provide here is a sample of some of our more recent investigations.
Figure: Pre- and post- values in EIM multifrequency resistance values in 4-day animals. Note markedly reduced values at low frequencies after injury (blue curves).
Healthy (right) and muscular dystrophy (left) mouse gastrocnemius muscle showing excess collagen deposition and various cell sizes in the mdx mouse muscle, the sine qua non of dystrophic muscle.
PGP 9.5 stainedskin and skin fiber density. Photomicrographs showing PGP 9.5-stained sections. Pictures were taken at 40X, scale bar = 50 μm.
ND RT: nondiabetic room temperature,
ND C: nondiabetic cold,
D RT: diabetic room temperature,
D C: diabetic cold.
Graph of IENF densities shows that diabetic animals exposed to a cold environment had the lowest IENF densities (n = 7 each control group, n = 6 each diabetic group). The data suggest that diabetic animals exposed to a cold environment have the smallest number of stained nerve fibers in the skin. White arrows indicate PGP 9.5-positive fibers. Mean ± SEM. ∗P =.037 for the interaction term. From Kasselman et al 2009
Impedance values in several different groups of young mice. Note the major changes in impedance values with increasing maturity.
Comparison of multiple excitability measures in motor and sensory nerves at the “standard threshold level” at 40% of the maximum amplitudes. The sensory nerves have the following characteristics in comparison to the motor nerves: (1) smaller threshold changes induced by weak and strong hyperpolarizing currents (marked as Hyperpol 40% and Hyperpol 70%); the threshold changes were similar to those induced by long depolarizing currents as shown as “Depol” (Panel A) and in Panel B; (2) greater S3 accommodation by long, strong hyperpolarizing current (Panel A); (3) smaller superexcitability and late subexcitability (Panel C); (4) greater strength–duration time constant as shown in Table 1. From Nodera and Rutkove, 2012