目的:研究1%Tetramethylpyrazine(TMP)在视网膜色素上皮细胞(RPE)变性,脉络膜血流和RPE细胞氧化应激中的作用。方法:在碘酸钠诱导的大鼠RPE变性研究中,1%TMP滴眼液预先处理1wk,3次/d,1wk后予碘酸钠舌下静脉注射,在2wk和4wk末,视网膜电图(ERG)测量c波。色素微球体技术分析高眼压状态下TMP对脉络膜血流的影响。Methylthiazoltetrazolium(MTT)分析TMP在各种氧化应激中对RPE的保护作用。结果:碘酸钠注射后2wk,碘酸钠组ERG的c波下降至对照组的36%(P<0.01)。4wk后,碘酸钠组下降至对照组的46%(P<0.01),而1%TMP+碘酸钠组下降至对照组的77%(P<0.01)。与碘酸钠组比较,1%TMP+碘酸钠组控制了67%的c波下降(P<0.05)。在脉络膜血流的测量中,30,60,和120min的结果显示,TMP显著增加脉络膜血流。在氧化应激部分,不同浓度的TMP在各种氧化应激损伤中,对RPE都有各种程度的保护作用。结论:浓度为1%Tetramethylpyrazine可以显著保护碘酸钠和氧化应激诱导的RPE变性,增加脉络膜血流,并可能在AMD的治疗中发挥作用。

AIM:To study the effects of Tetramethylpyrazine （TMP） on retinal pigment epithelium（RPE） degeneration,choroidal blood flow and oxidative stress of RPE cells. METHODS:The35mg/kg NalO₃-induced RPE degeneration rat eyes was given 25μg 1%TMP eye drops 3 times a day for 7 days before NalO₃ injection,and then 2 to 4 weeks after NalO₃ injection.RPE function was measured with cwave of electroretinogram（ERG）.Colored microsphere technique was used for in vivo experiments to determine the choroidal blood flow in ocular hypertensive（40mmHg） rabbit eyes.Methylthiazoltetrazolium（MTT） assay was used to study in vitro effect of TMP on various oxidants induced injury in the hRPE（ARPE-19（ATCC,Manassas, VA,USA））. RESULTS:Two weeks after NalO₃ injection,the amplitude of ERG c-wave fell markedly in NalO₃ group to 36%of control group（P<0.01）.No apparent difference was observed in TMP + NalO₃ group.Four weeks later,the NalO₃ group fell to 46%of control group（P<0.01）,while the TMP + NalO₃ group fell to only 77%of control group （P<0.01）.There was a 67%reversal of the ERG c-wave by TMP as compared to NalO₃ group（P<0.01）.The choroidal blood flow was significantly increased at all time points（at 30,60 and 120 minutes after TMP instillation） as compared with corresponding controls.TMP had no effect on hypoxia-（1%O₂）,t-BHP- and H₂O₂-induced damage in RPE cells.10μg/mL TMP could reverse 1 and 3mmol/L NaN₃-induced loss of viability of RPE by 18.5% （P<0.01） and 23%（P<0.01）,respectively.30μg/mL TMP could reverse 30 and 100mmol/L NalO₃ induced loss of viability of RPE by 18.1%（P<0.05） and 16.8%（P<0.01）,respectively. CONCLUSION:TMP can significantly protect RPE from NalO₃ induced degeneration in vivo and oxidative stress in vitro and can increase choroidal blood flow markedly in vivo.