AIM:To observe the changes of the vessel density of choriocapillaris in lens-induced myopia in guinea pigs, and to explore choroidal endothelin-1(ET-1), endothelin receptor A(ETAR)and receptor B(ETBR)expression changes and the effect of electroacupuncture.

METHODS: Fifty-four guinea pigs were randomly divided into normal control(NC), lens-induced myopia(LIM)and LIM+electroacupuncture(LIM+EA). The NC group was fed normally without intervention and the right eye in LIM group and LIM+EA group was coverd with a -6.00D lens to establish a myopia model. At 2 and 4wk, the refraction, axial length and the vessel density of choriocapillaris in groups were measured. The expression and protein content of ET-1, ETAR and ETBR mRNA in groups were detected by the real-time fluorescent quantitative PCR(quantitative polymerase chain reaction, q-PCR), enzyme-linked immunosorbent assay(ELISA)and immunohistochemistry.

RESULTS: At 2 and 4wk, compared with the the NC group, refraction and axial length in LIM group and LIM+EA group had significantly increased(all P<0.001). Compared with the LIM group, the refraction and axial length in LIM+EA group were decreased(all P<0.05). At 2 and 4wk, compared with the NC group,the vessel density of choriocapillaris was decreased(P<0.001)and the ET-1, ETAR and ETBR mRNA and protein levels in choroid were increased(all P<0.05)in LIM group. At 2 and 4wk, compared with the LIM group,the vessel density of choriocapillaris was decreased(P<0.01)and the ET-1, ETAR and ETBR mRNA and protein levels in choroid were increased in LIM+EA group.

CONCLUSION:In LIM guinea pigs, the choroidal blood flow decreased with the increased of refraction and axial length, which may affect ET-1 and its receptors through vascular shear force during the development of myopia. At the same time, electroacupuncture can improve choroidal blood flow through neuromodulation and affects the vascular shear stress to down-regulate the content of ET-1 and its receptor to delay the development of myopia.