L-THP reduced OXA accumulation and attenuated OXA-induced toxicity in primary DRG cells
Since OCT2 and MRP2 play vital roles in the uptake and efflux of OXA, respectively, and L-THP strongly inhibited OCT2 activity but not MRP2, we deduced that L-THP could reduce OXA accumulation and attenuate OXA-induced toxicity in DRG. Our results revealed that 40 μM of OXA significantly reduced the cell viability of primary DRG cells (to approximately 52% of the control), while co-treatment with L-THP (1-100 μM) increased the cell viability in a concentration-dependent manner (Figure 5a) ; for instance, 10 μM of L-THP increased the cell viability to 75% of the control, which indicates that L-THP may reduce the toxicity of OXA in DRG cells.
In agreement with the result of the cell viability test, L-THP (1-100 μM) reduced the accumulation of OXA in primary DRG cells in a concentration-dependent manner; for example, L-THP at 100 μM reduced the platinum accumulation in primary DRG cells to 32% of that in the OXA-alone group (Figure 5b) . In summary, our results suggest that L-THP can decrease the cellular accumulation of OXA and can thereby ameliorate OXA-induced toxicity in primary DRG cells.