Effect of Two-Week Swimming Training on the Expression of Irisin Protein in Lumbar Spine of Rats with Neuropathic Pain

Irisin is a myokine that is suggested to be a link between skeletal muscles and other tissues. Simultaneous presence of irisin and glutamate decarboxylase enzyme in purkinje cells of cerebellum led us to examine the potential role of irisin. As glutamate decarboxylase enzyme is responsible for converting glutamate excitatory neurotransmitter to GABA inhibitory neurotransmitters. Materials & Methods: Forty male Wistar rats (weight: 180±20 g) were assigned to five groups as follows: 1) CCI neuropathic pain with swimming training (CCIST); 2) CCI neuropathic pain without swimming training (CCI); 3) No CCI neuropathic pain with swimming training (ST); No CCI neuropathic pain without swimming training (Control); 5) CCI sham surgery (Sham). CCI and CCIST groups underwent peripheral nerve injury by four loose ligatures on the sciatic nerve. The swimming training program included two weeks of swimming (5 sessions per week, 30-60 min per session). The protein expression of irisin in L4-L6 regions was evaluated by western blotting technique. Findings: Irisin expression in the CCIST2 (P=0.039) and ST2 (P=0.016) groups was lower than in the CCI group. However, there was no significant difference between two training groups. Discussion & Conclusions: If we assume a similar role for irisin in the nervous system as in adipose tissue, the lower level of irisin in the two training groups can be justified as it is less needed to reduce ATP production as an excitatory neurotransmitter in the spine.a