Background: We tested the hypothesis that extracorporeal shock wave (ECSW) therapy can effectively protect sciatic nerve (SN) from diabetes mellitus (DM)-induced neuropathy in leptin-deficient (ob/ob) mice.
Methods and results: Eighteen-week C57BL/6 mice (n=8) served as age-matched controls (group 1) and ob/ob mice (n=16) were categorized into DM (group 2) and DM + ECSW (0.12 mJ/mm(2) for 4 times of 200 impulses at 3-week intervals) (group 3). The animals were sacrificed two weeks post-ECSW. In vitro results showed that the protein expressions of oxidative stress (NOX-1, NOX-2, oxidized protein), inflammation (MMP-9, TNF-α, iNOS), apoptosis (Bax, cleaved caspase-3, & PARP), and DNA-damage marker (γ-H2AX) were significantly higher in RT4-D6P2T (schwannoma cell line) treated by menadione (25 µM) compared with control group and were significantly reversed after ECSW (0.12 mJ/mm(2), 200 impulses) (all p<0.001). mRNA expressions of inflammation (MMP-9, TNF-α, iNOS), oxidative stress (NOX-1, NOX-2) and apoptosis (Bax, caspase-3) in SN were significantly higher in group 2 than in group 1 and were significantly reversed in group 3, whereas the mRNA expressions of anti-oxidants (HO-1, NQO1) progressively increased from group 1 to group 3 (all p<0.001). Cellular expressions of F4/80+, CD14+, γ-H2AX+ cells, and number of vacuolar formation in SN showed a pattern identical to that of inflammation markers among all groups (all p<0.001). Microscopic findings of Schwann cells and myelin-sheath scores, and number of eNOS+ cells in SN showed a reversed pattern compared to that of inflammation among all groups (all p<0.001).
Conclusions: ECSW therapy protected SN against DM-induced neuropathy.
Keywords: Diabetic neuropathy; extracorporeal shock wave; inflammation; oxidative stress.