枸杞多糖对高压诱导凋亡的视网膜神经节细胞延迟整流钾电流的影响

Effects of lycium bararum polysaccharides on delayed rectifier K^+ current in high pressure-induced apoptosis of retinal ganglion cells

目的观察枸杞多糖(lycium bararum polysaccharides,LBP)对体外高压诱导调亡的视网膜神经节细胞(retinal ganglion cells,RGCs)钾电流的影响。方法生后2~3 d的SD乳大鼠RGCs原代培养,分为对照组、加压组和LBP组,对照组为常规培养6 d;加压组为常规培养6 d后用自行设计的加压装置加压1 h 80 mm Hg(1 k Pa=7.5 mm Hg);LBP组为常规培养5 d后,加入LBP共培养24 h后,再加压80 mm Hg 1 h。通过全细胞膜片钳技术观察各组钾电流、半数最大激活电压(V1/2)、斜率(K)、最大电导(Gmax)的变化。结果加压能使电流幅度显著增加,LBP能抑制加压引起的电流增加。在刺激电位为-10~60 m V时,加压组的电流密度明显大于对照组,差异有统计学意义(均为P<0.01,n=5/6);LBP组电流密度明显小于加压组,差异有统计学意义(均为P<0.01,n=6/8)。三组钾电流V1/2总体差异有统计学意义(F=55.60,P<0.01),加压组V1/2(11.65±1.30)m V与对照组(21.42±1.33)m V、LBP组(19.33±13.75)m V比较,差异均有统计学意义(均为P<0.01);LBP组V1/2与对照组V1/2比较,差异无统计学意义(P>0.05)。三组K值分别是17.09±1.24、16.58±1.18、18.13±1.29,总体差异无统计学意义(F=1.39,P>0.05)。三组Gmax总体差异有统计学意义(F=3.77,P<0.05),加压组Gmax(0.59±0.13)与对照组Gmax(0.46±0.06)、LBP组Gmax(0.46±0.07)比较,差异均有统计学意义(均为P<0.05);LBP组Gmax与对照组Gmax比较,差异无统计学意义(P>0.05)。结论 LBP能抑制加压引起的RGCs钾电流增加,对RGCs具有保护作用。

Objective To investigate the effects of lycium bararum polysaccharide（LBP）on the delayed rectifier K^＋ current（I_k） in high pressure-induced apoptosis of rat retinal ganglion cells（RGCs）.Methods The retina of newborn SD rats were dissociated into cell suspension with trypsin digestion,RGCs was cultured and divided into control group,pressure group and LBP group,the cells in control group was cultured regularly for 6 days,cells in the pressure group was cultured regularly for 6 days and pressured 80 mmHg（1 kPa = 7.5 mmHg） for 1 hour,cells in the LBP group was cultured regularly for 5 days and LBP was added into the medium,24 hours later,cells was pressured 80 mmHg for 1 hour.Then,I_k were recorded from RGCs in the three groups by using whole-cell patch-clamp techniques to get the V_（1/2）（half maximum activation voltage）,K（slope）,Gmax（maximum conductance） from I_k.Results The I_k was higher than that in the control group,and LBP suppressed the current amplitudes of I_k.At the test potential from- 10 mV to 60 mV,the current density in pressure group was higher than that in the control group,the difference was significant（all P〈0.01,re = 5/6）,otherwise,the current density in LBP group was lower than that in the pressure group,the difference was significant（all P〈0.01,n= 6/8）.The voltage for V_（1/2） in the three groups were significant different（F = 55.60,P〈0.01）,the data revealed that V_（1/2） was（11.65± 1.30） mV in the pressure group,showing a significant decline in comparison with（21.42 ±1.33）mV in control group and（19.33 ±13.75）mV in LBP group（all P〈0.01）,but no significant difference was seen in V_（1/2） between the LBP group and control group（P〉0.05）.The K was 17.09 ± 1.24,16.58 ± 1.18,18.13 ± 1.29 in control group,pressure group and LBP group,there was no statistical difference（F=1.39,P〉0.05）.Gmax in the three groups were significant difference（F = 3.77,P〈0.05）,the value of Gmax（0.59 ± 0.13） in pressure group was higher than control group（0.46 ±0.06） and LBP group（0.46 ±0.07）（all P〉0.05）,there was no significant difference between the LBP group and control group（P〈0.05）.Conclusion The pressure-induced I_k current enhancement in RGCs can be eliminated by LBP,which play an important role in the protection of RGCs.