微重力环境下大鼠眼底血流动力学及视网膜、脉络膜厚度的变化

Changes of ocular fundus hemodynamics and retinal and choroidal thickness after tail suspension for 2 weeks in rats

目的探讨微重力环境下大鼠视网膜中央动脉(CRA)血流动力学及视网膜、脉络膜厚度的变化。方法雄性SD大鼠8只,采用自身对照法分为尾吊前及尾吊1、4、7、14 d等5个时间段,采用尾悬吊法建立模拟微重力环境大鼠模型,利用彩色多普勒超声诊断仪测量大鼠CRA收缩期最大血流速度(PSV),利用EDI SD-OCT测量大鼠视网膜、脉络膜厚度。结果尾吊后不同时间段大鼠PSV均较尾吊前下降(P<0.05);尾吊后1 d大鼠PSV与尾吊4 d、7 d比较差异无统计学意义(P>0.05),但明显低于尾吊14 d时,差异有统计学意义(P<0.05)。尾吊前与尾吊后各时间段大鼠视网膜厚度差异均无统计学意义(P>0.05)。尾吊后不同时间段大鼠脉络膜厚度均较尾吊前增加(P<0.05);与尾吊1 d比较,尾吊4、7、14 d大鼠脉络膜厚度均明显增加(P<0.05)。结论模拟2周微重力环境下大鼠眼底血流速度降低,脉络膜厚度增加,但视网膜厚度未发生明显变化。

Objective To investigate the effects of simulated 2-week microgravity on the ocular fundus hemodynamics of central retinal artery and the retinal and choroidal thickness in autogenous rats.Methods Eight healthy SD rats were designed in self-control,designed for the control before tail suspension,the tail suspension for 1,4,7 and 14 d.A rat model of simulated microgravity method was established by tail suspension.The peak maximum systolic velocity (PSV) of central retinal artery (CRA) in rats was detected and analyzed by color Doppler ultrasonography.The retinal and choroidal thicknesses were measured by the enhanced depth imaging spectral-domain optical coherence tomography (EDI SD-OCT).Results The PSV value in each different period after tail suspension was decreased compared with that in the control before tail suspension (P<0.05).There was no significant difference in PSV value between the tail suspension for 1 d and both the tail suspension for 4 d and 7 d (P>0.05),but there was a significant difference between the tail suspension for 1 d and the tail suspension for 14 d (P<0.05).There was no significant difference in retinal thickness between the control and the each different periods after tail suspension (P>0.05).The choroidal thickness was lower in the control before tail suspension than that in each different period after tail suspension (P<0.05).Compared with the tail suspension for 1 d,the choroidal thickness of the rats was significantly increased in the tail suspension for 4,7 and 14 d respectively (P<0.05).Conclusions Two-week simulated microgravity environment has significant effects on the fundus blood flow and choroid thickness in rats,but has no obvious effect on the retinal thickness in rats.The fundus flow velocity would decrease and choroid thickness would increase with the prolongation of the tail suspension time.