Antagonistic Effect Of Vitamin C On Neurotoxicity Of The Dorsal Root Ganglion (DRG) Neurons Caused By Colistin

Colistin plays a very powerful role in killing susceptible Gram-negative strains and is used intreatment of the multidrug-resistant Gram-negative infections. Although colistin has beendemonstrated its renal toxicity and neurotoxicity in the clinical application and has been abandonedfor decades, it was re-taken by the people because of its strong bactericidal effect and being hard toproduce drug resistance characteristics with the increasing of Gram-negative bacteria infection, forinstance Pseudomonas aeruginosa and Klebsiella pneumoniae in recent years. So, in this study, wewill explore to reduce or eliminate the toxic effects of colistin, which will exhibit very importanttheoretical and clinical significance.As an anti-toxic drugs and antioxidants, vitamin C is widely used in the treatment of a varietyof drug-induced side effects. The latest research showed that vitamin C has very good antagonismto colistin nephrotoxicity, however, less study showed that vitamin C had a antagonism role on theperipheral neurotoxicity caused by colistin.In this study, we used the4d mouse primary dorsal root ganglia （DRG） cells as the researchobject by in vitro culture techniques. The relative activity of cells, Caspase-3activity, theconcentration of acetylcholine, LDH and SOD in the cell culture medium were measured to discusswhether vitamin C had the antagonistic effect on peripheral nerve toxicity of colistin.The half inhibitory concentration (IC₅₀) of sulfate colistin on dorsal root ganglion cell activitywas250g·mL^-1. The250g·mL^-1of colistin was used as the mother liquor to prepare the testedculture mediums containing the final concentrations of vitamin C250,500,750,1000,1250μg·mL^-1in the experimental groups. Primary mouse dorsal root ganglion cells were cultured for24h at37°C and5%CO₂, morphological changes were observed and the cells relative activity value,the activity of Caspase-3and the LDH levels, acetylcholine content and SOD activity of cellsupernatant were measured. The experimental results showed that:（1） When the vitamin C concentration reaches a certain amount(1000μg·mL^-1), it canantagonize the morphology demage of dorsal root nerve by colistin.（2） Vitamin C can reduce the level of LDH in the cell culture medium and effectively reducethe destruction of membrane.（3） The MTT value, activities of Caspase-3, acetylcholine, LDH and SOD in theexperimental group of vitamin C changed significantly compared with the control group, and the impact of these indicators expressed with a dose-dependent trend.In conclusion, Vitamin C can antagonize dorsal root neurotoxicity of colistin by morphologicalobservation.Certain doses of vitamin C can make the cytotoxicity caused by colistin sulfate to berecovered, for example, change of relative activity of the cells, increase of the activity of Caspase-3and the abnormal of the concentration of acetylcholine, LDH and SOD levels. Vitamin C hasantagonize to the neurotoxicity caused by colistin, and may be due to its own antioxidion effect.