Résumé
Objective:To investigate whether ferroptosis of nerve cells exists in a rat model of neuropathic pain (NP), and to explore the mechanism of O 3 treatment of NP. Methods:Sixty male SD rats were randomly divided into three groups: neuropathic pain model group (NP group), sham operation group (Sham group) and ozone group (O 3 group). The partial sciatic nerve ligation was used in the NP and O 3 groups to construct a neuropathic pain model. The Sham group was subjected to sham surgery. In the O 3 group, 15 μl of O 3 (40 μg/ml) was injected locally at the injury site, and the NP and Sham were injected with the same amount of air, once per day. The mechanical contraction response threshold (MWT) and thermal contraction latency (TWL) of the rats were measured 1 day before the surgery (T0) and 1, 3, 7, 14 days after the surgery (T1 to T4). The spinal cord segments of rats were collected. The expression levels of glutathione peroxidase 4 (GPX4) and long chain fatty acid coenzyme A synthetase 4 (ACSL4) at T1 to T4 was detected using Western Blot. The number of NeuN+ neuron cells in the spinal dorsal horn at T4 was detected using immunofluorescence technology. The specific changes of ferroptosis at T4 was observed by a transmission electron microscopy. Iron deposition in the spinal dorsal horn at T1 to T4 was measured using ferroptosis kits. Results:Compared with the Sham group, rats in the NP group and O 3 group showed decreasing of MWT decreased and shortening of TWL at T2 to T4, decreasing of NeuN+ neurons in spinal dorsal horn at T4, specific changes of ferroptosis in mitochondria at T4, and increasing of iron content in nerve tissue at T2 to T4. Compared with the Sham group, rats in NP group showed decreasing of GPX4 level and increasing of ACSL4 level. Compared with the NP group, rats in the O 3 group showed increasing of MWT and prolonging of TWL at T2 to T4, increasing of the GPX4 level and decreasing of ACSL4 level at T2 to T4, increasing of the number of NeuN+ neuron cells in the spinal dorsal horn, improving of the mitochondrial atrophy of nerve cells, and decreasing of the iron content in nerve tissue at T2 to T4. The above results are statistically significant (all P<0.05). Conclusions:The mechanism of O 3 in treating neuropathic pain may be through inhibition of iron death.