Celecoxib ameliorates diabetic neuropathy by decreasing apoptosis and oxidative stress in dorsal root ganglion neurons via the miR-155/COX-2 axis.

ABSTRACT

Celecoxib (CXB) is the only clinical cyclooxygenase-2 (COX-2) inhibitor. Oral administration of CXB in experimental diabetic mice effectively relieved the symptoms of diabetic neuropathy (DN); however, the molecular mechanism remains unclear. The present study aimed to investigate the potential molecular mechanisms of CXB in the treatment of DN. An in vitro cellular model of DN was produced by stimulating dorsal root ganglion (DRG) neurons with high glucose. Cell viability and apoptosis were assessed by Cell Counting Kit-8 assays and flow cytometry, respectively. Reactive oxygen species (ROS) kits, ELISA kits and western blotting were used to determine oxidative cellular damage. The expression level of microRNA (miR)-155 was analyzed by reverse transcription-quantitative PCR. The starBase database and dual-luciferase assays were performed to predict and determine the interaction between miR-155 and COX-2. Protein expression of neurotrophic factors, oxidative stress-related proteins and COX-2 were analyzed by western blotting. Incubation with high glucose led to a decrease in DRG neuron cell viability, facilitated apoptosis, downregulated NGF and BDNF expression, increased ROS and MDA generation and decreased SOD activity. Treatment with CXB significantly protected DRG neurons against high glucose-evoked damage. CXB promoted the expression of miR-155 and COX-2 was revealed to be a direct target of miR-155. Inhibition of COX-2 enhanced the protective effect of CXB on DRG neurons and that treatment with an miR-155 inhibitor partially rescued this effect. The present study demonstrated the involvement of the miR-155/COX-2 axis in the protective effect of CXB against high glucose-induced DN.