Downregulation of MicroRNA-33-5p Protected Bupivacaine-Induced Apoptosis in Murine Dorsal Root Ganglion Neurons Through GDNF.

In this work, we evaluated the functional role of microRNA-33-5p (miR-33-5p) in regulating bupivacaine (Bv)-induced neural apoptosis in dorsal root ganglion (DRG) cells. DRG was extracted from adult mice and treated with BV in vitro. A TUNEL assay was applied to assess neural apoptosis among DRG cells. A qRT-PCR assay was applied to assess miR-33-5p expression among BV-treated DRG cells. MiR-33-5p was genetically knocked down in DRG cells. Its effect on BV-induced neural apoptosis was further evaluated by TUNEL assay. Correlation between miR-33-5p and its putative downstream target gene, glial cell-derived neurotrophic factor (GDNF), was assessed by dual-luciferase activity and qRT-PCR assays, respectively. GDNF was then inhibited in miR-33-5p-downregulated DRG cells to further assess its functional regulation in BV-induced neural apoptosis. BV induced significant neural apoptosis, in a dose-dependent manner, in DRG cells in vitro. MiR-33-5p was upregulated by BV treatment, also in a dose-dependent manner in DRG cells. On the other hand, downregulation of miR-33-5p protected BV-induced DRG neural apoptosis. GDNF was shown to be inversely correlated with miR-33-5p in BV-treated DRG cells. Moreover, inhibiting GDNF was able to reverse the protection of miR-33-5p-downregulation on BV-induced DRG neural apoptosis. MiR-33-5p, through its inverse regulation on DGNF gene, modulates anesthesia-induced neural apoptosis in DRG cells.