Intra-epidermal Nerve Fibers Density and Nociception in EPO-Treated Type 1 Diabetic Rats with Peripheral Neuropathy - Tissue-Protective Cytokines: Methods and Protocols - page 196

Fig. 1 Flow chart of the studies. Two studies were performed with rats in which
were tested the efficacy of EPO in protecting (protective schedule) or reversing
(therapeutic schedule) nerve dysfunction in STZ-induced diabetes and their cor-
relation with IENF density. For study 1 (protection), diabetic and control rats were
treated with rhEPO 40 g/kg of b.w., i.p., three times per week for 5 weeks start-

ing on week 2 following STZ. For therapeutic schedule (study 2) the same EPO
protocol was applied, starting 6 weeks after diabetes induction and lasting an
additional 5 weeks

μ

In the therapeutic schedule, treatment with rhEPO was
started 6 weeks after diabetes induction and lasted an addi-
tional 5 weeks with the same EPO treatment protocol.
3. In addition to general observations, growth and glycemia,
specific measurements were performed. Among them we eval-
uate nociceptive thresholds, as markers of painful neuropathy
(which correlate with small-fiber neuropathy), NCV and Na + /
K + -ATPase-activity, largely considered the hallmarks of diabetic
neuropathy. We have previously shown that in normal rats
overall quantification of IENF density correlate with changes
in NCV (see Note 6).

The thermal nociceptive threshold response utilizes a polysynaptic
pathway involving higher centers, whereas the mechanical nocicep-
tive threshold is a monosynaptic response. Rats were accustomed
to the devices 3 days before performing the tests.
The nociceptive threshold to radiant heat was quantified using the
hot plate paw withdrawal test, as previously described ( 29 ). Briefly,
a 40 cm high Plexiglas cylinder was suspended over the hot plate
(Ugo Basile, Comerio, Italy), and the temperature was maintained at

3.1 Nociceptive
Thresholds