Therapeutic dosage of ozone inhibits autophagy and apoptosis of nerve roots in a chemically induced radiculoneuritis rat model.

OBJECTIVE: Radiculoneuritis characterizes by the neurogenic pain along the back of patients. This study aims to investigate the therapeutic effects of ozone on radiculoneuritis and the associated mechanisms in rat models.

MATERIALS AND METHODS: A chemical radiculoneuritis rat model was successfully established. The rats were divided into 3 groups, including radiculoneuritis Model rats group (Model group, n=18), Ozone therapy group (n=18), and Normal control group (n=18). Ozone was administered at a dosage of 1 mg/kg/day. The electron microscope was used to observe autophagosomes in the cytoplasm. Immunohistochemistry assay was performed to examine cleaved caspase 3 and double-labeled immunofluorescence assay was used to detect light chain 3B (LC3B) and neuronal nuclear antigen (NeuN) expression. Quantitative Real-time PCR (RT-PCR) and Western blot were employed to evaluate the expression of LC3B, Beclin 1, phosphodiesterase 2A (PDE2A), and nuclear factor-kB p65 (NF-kBp65).

RESULTS: Ozone significantly decreased autophagosomes formation and inhibited autophagy of nerve root cells in radiculoneuritis rat model. Ozone significantly decreased levels of autophagosomes initiator, LC3B, compared to Model group (p<0.05). Ozone significantly decreased cleaved caspase 3 expressions and alleviated apoptosis of nerve root cells compared to that of Model group (p<0.05). According to RT-PCR and Western blot assay, ozone significantly suppressed LC3B and Beclin 1 expression compared to that of Model group (p<0.05). Ozone significantly decreased PDE2A and NF-kB p65 expression compared to that of the Model group (p<0.05).

CONCLUSIONS: Therapeutic dosage of ozone inhibits autophagy by suppressing LC3B and Beclin 1 expression and reduces apoptosis by blocking NF-kB signaling pathway.