雷帕霉素对豚鼠形觉剥夺性近视的干预作用及相关机制研究

目的 探讨球结膜下注射雷帕霉素对豚鼠形觉剥夺性近视(FDM)的干预作用及相关机制.方法 选取2～3周龄豚鼠80只(80眼),雌雄不限,随机分为4组:空白对照组、FDM组、雷帕霉素组、FDM+雷帕霉素组;空白对照组不做任何处理;FDM组单纯缝合豚鼠右眼眼睑;雷帕霉素组于实验第1天、第7天豚鼠右眼球结膜下注射雷帕霉素50μ...

Effects of rapamycin on the form-deprivation myopia in guinea pigs and its related mechanisms

Objective　To investigate the effect of subconjunctival injection of rapamycin on the form-deprivation myopia (FDM) of guinea pigs and its related mechanisms.Methods　Together 80 healthy guinea pigs (80 eyes), male or female, aged 2-3 weeks, were randomly divided into 4 groups: blank control group, FDM group, rapamycin group, and FDM+ rapamycin group. Guinea pigs in the blank control group left untreated; in the FDM group, the right eyelids of pigs were only sutured; 1 day and 7 days of the experiment, 50 μg rapamycin was injected subconjunctival in the rapamycin group while the right eyelids were sutured after subconjunctival injection in the FDM+ rapamycin group. The axial length and diopter of each group were recorded before and 7 days and 14 days of the experiment, and the eyeballs were taken for periodate Schiff’s staining (PAS staining) and retinal transmission electron microscope to observe the changes of retinal morphology. The sclera of each group of guinea pigs was taken for RT-PCR to measure mRNA expression of scleral tissue mTOR, matrix metalloproteinase-2 (MMP-2), α-smooth muscle actin (α-SMA) and transforming growth factor β1 (TGF-β1); Western blot was used to detect the protein expression of AKT, p-AKT, mTOR, and p-mTOR in the scleral tissue of guinea pigs in each group.Results　Compared with the blank control group, the right eyes of axial length and diopter in the FDM group increased on day 7 and 14 of the experiment, resulting in relative myopia. The relative expression of MMP-2 and α-SMA mRNA increased while the relative expression of TGF-β1mRNA decreased, and the differences were statistically significant (all P<0.05). Compared with the blank control group, there was no significant difference in the relative expression of mTOR mRNA and AKT, p-AKT, mTOR and p-mTOR protein in the sclera of guinea pigs in the FDM group (all P＞0.05), and the retina became thinner and the structure of each layer becomes disordered and loose. There was no significant difference in axial length and diopter of right eye between rapamycin group and blank control group on day 7 and 14 of the experiment (all P>0.05), and there was no significant change in retinal morphology. There was no significant difference in right eye axial length and diopter between FDM+rapamycin group and FDM group on day 7 of the experiment (both P>0.05), while on day 14 of the experiment, the axial length and diopter of the right eye decreased, and the differences were statistically significant (all P<0.05). The relative expression of TGF-β1 mRNA increased, while the relative expression of MMP-2, α-SMA and mTOR mRNA and AKT, p-AKT, mTOR and p-mTOR protein decreased, and the difference was statistically significant (all P<0.05).Conclusion　Subconjunctival injection of rapamycin can delay the formation of FDM in guinea pigs, which may play a role in inhibiting PI3K/AKT/mTOR signal pathway and regulating the expression of MMP-2, TGF- β1, α-SMA and mTOR in the sclera, and it has no effect on the normal retinal structure.