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

目的　观察枸杞多糖（ｌｙｃｉｕｍｂａｒａｒｕｍｐｏｌｙｓａｃｃｈａｒｉｄｅｓ，ＬＢＰ）对体外高压诱导调亡的视网膜神经节细胞（ｒｅｔｉｎａｌｇａｎｇｌｉｏｎｃｅｌｌｓ，ＲＧＣｓ）钾电流的影响。方法　生后２～３ｄ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６ｄ；加压组为常规培养６ｄ后用自行设计的加压装置加压１ｈ８０ｍｍＨｇ（１ｋＰａ＝７．５ｍｍＨｇ）；ＬＢＰ组为常规培养５ｄ后，加入ＬＢＰ共培养２４ｈ后，再加压８０ｍｍＨｇ１ｈ。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－１０～６０ｍＶ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）ｍＶ与对照组（２１．４２±１．３３）ｍＶ、ＬＢＰ组（１９．３３±１３．７５）ｍＶ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。

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

Objective To investigate the effects of lycium bararum polysaccharide ( LBP) on the delayed rectifier K+ current ( Ik ) 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 ( I kPa = 7. 5 mmHg) for I 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 I hour. Then,/k were recorded from RGCs in the three groups by using whole-cell patch-clamp techniques to get the Vl/2 ( half maximum activation voltage) ,K( slope) ,Gmax ( maximum conductance) from /k. Results The Ik was higher than that in the control group , and LBP suppressed the current amplitudes of /k. At the test potential from - 10 mV t0 60 mV,the current density in pressure group was higher than that in the control group ,the difference was significant ( all P < 0. 01 .n = 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 Vl12 in the three groups were significant different ( F = 55. 60 .P < 0. 01 ) , the data revealed that Vl/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. 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 Ik current enhancement in RGCs can be eliminated by LBP , which play an important role in the protection of RGCs.