外源性褪黑素对豚鼠形觉剥夺性近视褪黑素受体、iNOS、c-fos表达的影响

Effect of exogenous melatonin on expression of melatonin receptor,iNOS and c-fos in guinea pigs with form deprived myopia

目的探讨外源性褪黑素(melatonin,MLT)在豚鼠形觉剥夺性近视(form deprived myopia,FDM)形成中的作用。方法将40只7d龄豚鼠,随机分为4组,每组10只,右眼建立FDM模型,左眼为自身对照眼。A组为对照组,腹腔注射5mL.kg-1生理盐水,B、C、D组为MLT干预组,腹腔注射不同剂量MLT(5mg.kg-1、10mg.kg-1、20mg.kg-1)。8周后A超测量双眼眼轴长度,行检影验光检测双眼屈光度,免疫组织化学法分析MLT受体MT1、诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS)及c-fos的表达。结果 A组遮盖眼屈光度数、眼轴长度,视网膜中iNOS、MT1、c-fos表达分别为(-7.86±0.26)D、(8.51±0.16)mm、0.4836±0.0247、0.3179±0.0344、0.2282±0.0246。不同剂量MLT作用于FDM眼后,随外源性MLT剂量的增加,以上指标变化被明显抑制甚至逆转。C组FDM眼的屈光度数、眼轴长度,视网膜中iNOS、MT1、c-fos平均光密度值表达分别为(-4.30±0.59)D、(8.04±0.24)mm、0.3733±0.0427、0.3743±0.0447、0.3713±0.0786;D组分别为(-3.41±0.88)D、(7.43±0.39)mm、0.3079±0.1261、0.4055±0.0919、0.4458±0.0974。C组、D组各指标分别与A组比较差异均有统计学意义(均为P<0.05);但B组与A组之间的差异均无统计学意义(均为P>0.05)。结论外源性MLT能抑制甚至逆转FDM鼠屈光度、眼轴长度及视网膜iNOS、MT1、c-fos的免疫活性,同时发现高剂量组较低剂量组结果明显。据此可推断,外源性MLT对FDM的形成有抑制作用。

Objective To investigate the effect of exogenous melatonin（MLT）in the formation of form deprived myopia（FDM）in guinea pigs.Methods Forty guinea pigs with 7 days old were divided into four groups,10 cases in each group,FDM model were established in the right eyes,and the left eyes were set as control.Group A：The control group;Group B,C,D：Intraperitoneal injection of different doses of MLT（5 mg·kg-1,10 mg·kg-1,20 mg·kg-1）.The axial length was measured with A-mode ultrasound,and the eyes refractive state was determined by streak retinoscopy,MLT receptor MT1,iNOS and c-fos were analysed with immunohistochemistry after 8 weeks.Results In the FDM eyes of group A,the diopter,axial length,expression of iNOS,MT1 and c-fos were（-7.86±0.26）D,（8.51±0.16）mm,0.483 6±0.024 7,0.317 9±0.034 4 and 0.228 2±0.024 6,the FDM model was successfully established.Intra-peritoneal injection of different doses MLT,as compared with group A,these indexes were significantly inhibited or even reversed with doses of exogenous MLT increased.In the FDM eyes of group C and D,the diopter,axial length,expression of iNOS,MT1 and c-fos were（-4.30±0.59）D and（-3.41±0.88）D,（8.04±0.24）mm and（7.43±0.39）mm,0.373 3±0.042 7 and 0.307 9±0.126 1,0.374 3±0.044 7 and 0.405 5±0.091 9,0.371 3±0.078 6 and 0.445 8±0.097 4,respectively;There were statistical differences between group C,D and group A（all P〈0.05）,but there was no difference between group A and B（P〉0.05）.Conclusion Exogenous MLT can inhibite or even reverse the refraction,axial length and immunoreactivity of iNOS,MT1,c-fos in the FDM,the effects in the high dose groups are more significant than that in the low dose group.From these we can deduce that the exogenous MLT inhibites the formation of FDM.