Small-molecule GSK-3 inhibitor rescued apoptosis and neurodegeneration in anesthetics-injured dorsal root ganglion neurons.
BACKGROUND
Application of general anesthetics may induce neurotoxicity in dorsal root ganglia (DRG) neurons. In this study, we examined the possible protective mechanism and associated signaling pathways of small-molecule glycogen synthase kinase-3 (GSK-3) inhibitor, SB216763, in bupivacaine-injured mouse DRG neurons in vitro.


METHODS
In vitro DRG explant of 6-week old mice was treated with 5mM bupivacaine to induce neurotoxicity. The explants were also pre-treated with SB216763 for 72h. Neural protection of SB216763 on bupivacaine-injured DRG neurons was investigated by TUNEL assay, neurite outgrowth assay and western blot assay, respectively. Possible downstream gene of GSK-3 signaling pathway, protein kinase C (PKC) was knocked down by siRNA in DRG explant. Its function in regulating GSK-3 inhibition induced DRG neural protection was also examined by TUNEL, neurite outgrowth and western blot assays.


RESULTS
Pre-treatment of SB216763 significantly ameliorated bupivacaine induced apoptosis and neurite loss in DRG neurons. Western blot showed that, in addition to the decrease of phosphorylated-GSK-3 α/β protein, SB216763 increased PKC and decreased caspase-3 (Casp-3) in bupivacaine-injured DRG neurons. SiRNA-mediated PKC knockdown was able to reverse the neural protection of SB216763 in bupivacaine-injured DRG neurons. Western blot showed that PKC knockdown increased phosphorylated-GSK-3 α/β and Casp-3 protein in DRG neurons, confirming that PKC was directly involved in GSK-3-inhibition induced neural protection in DRG.


CONCLUSIONS
GSK-3 inhibitor SB216763, through PKC, is effective in protecting anesthetics-induced neurotoxicity in DRG.
Department of Anesthesiology, Daqing Oil Field General Hospital, Daqing, Heilongjiang Province, 163001, China. Electronic address: yutch991@aol.com.
Tianchao
T
Yu
Department of Anesthesiology, Daqing Oil Field General Hospital, Daqing, Heilongjiang Province, 163001, China.
Wanchun
W
Lin
D000777:Anesthetics / Q000009:adverse effects*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002045:Bupivacaine / Q000009:adverse effects; D053148:Caspase 3 / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D005727:Ganglia, Spinal / Q000187:drug effects / Q000473:pathology*; D055785:Gene Knockdown Techniques; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D007211:Indoles / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D008810:Mice, Inbred C57BL; D016501:Neurites / Q000187:drug effects / Q000473:pathology; D009474:Neurons / Q000187:drug effects / Q000473:pathology*; D000066829:Neuroprotection / Q000187:drug effects; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects; D054852:Small Molecule Libraries / Q000494:pharmacology*
D000777:Anesthetics; D007211:Indoles; D008301:Maleimides; D047428:Protein Kinase Inhibitors; C417521:SB 216763; D054852:Small Molecule Libraries; D011493:Protein Kinase C; D038362:Glycogen Synthase Kinase 3; D053148:Caspase 3; D002045:Bupivacaine
Caspase-3; Dorsal root ganglion; GSK-3; PKC; SB21673