Effects of differentconcentrations of FK506 on the growth of dorsal root ganglia neuron in new-born rats

Abstract

：Objective To determinethe concentrations of FK506 suitable to the growth of the dorsal root ganglia neuron(DRGn). Methods The dorsal root ganglia (DRG) of 8 new-born SD rats (within 24 hours) werecollected to remove the epineurium of the DRG. After dissection into pieces of about 0.1mm~3 in size, the DRG fragments were digested by 0.25% trypsin. Then DRGn was purified andcultured for 96 hours before establishment of 4 groups: blank-control group (Group A), 1×10~(-10)mol/L FK506 (Group B), 1× 10~(-9) mol/L FK506 (Group C) and 1×10~(-8) mol/L FK506 (GroupD). After culture of the DRGn for another 48 hours, the growth of neurons was assessed byNF200 immunofluorescence, the vitality of the DRGn by MTT method and the expression ofGAP-43's mRNA by RT-PCR. Results The MTT value and GAP-43mRNA expression in group A wererespectively 0.472±0.030 and 0.375±0.016, in group B were respectively 0.481±0.013 and0.388±0.009, in group C were respectively 0.573±0.016 and 0.490±0.003, and in group Dwere respectively 0.342±0.004 and 0.283±0.009. There were no statistical significancesbetween groups A and B (P>0.05), but when group A was compared with groups C and D,statistical significances existed (P< 0.05). The statistical significances also existedwhen group B was compared with groups C and D (P<0.05). There were statisticalsignificances between groups C and D (P<0.05) . Conclusions The 1×10~(-9) mol/Lconcentration of FK506 may provide best neurotrophy and neuroprotection for the growth ofDRGn. FK506 of 1×10~(-10) mol/L may also provide neurotrophy and neuroprotection for thegrowth of DRGn, but FK506 of 1×10~(-8) mol/L may have inhibitory effects on the neurons.