Vitreous alterations occur from early stages and continue through the normal aging, with gradual lamellae formation and the appearance of liquefied spaces, which eventually leads to complications, such as retinal tear, retinal detachment, and intravitreal hemorrhage. The aim of the present study was to investigate the expression of let-7 miRNA family in the vitreous and retina in newborn (1-3- day-old), young adult (2-month-old), and aging (12-month-old) rats, as well as their role as regulators of vitreous components. MicroRNAs are small, non-coding RNAs that post-transcriptionally regulate gene expression. Our results showed detection of all investigated let-7 isoforms (let-7a, let-7b, let-7c, let-7d, let-7e, let-7f and let-7i) in the retina and vitreous. Although most let-7 members were significantly upregulated in the vitreous during development, only let-7b, let-7c, and let-7e followed this same expression pattern in the retina. Let-7b and -7c increased in aging vitreous as well, and were expressed in vitro by Müller glial cells and their extracellular vesicles. Moreover, let-7 targeted hyaluronan synthase 2 (Has2) mRNA, a synthesizing enzyme of hyaluronan. These observations indicate that let-7 function is important during retina and vitreous development, and that isoforms of let-7 increased with aging, potentially modulating hyaluronan content.

玻璃体改变从早期发生并持续到正常衰老，逐渐形成薄片并出现液化空间，最终导致并发症，如视网膜撕裂、视网膜脱离和玻璃体内出血。本研究的目的是调查 let-7 miRNA 家族在新生儿（1-3 天大）、青年（2 个月大）和老龄（12 个月大）玻璃体和视网膜中的表达。 -old) 大鼠，以及它们作为玻璃体成分调节剂的作用。MicroRNA 是小的非编码 RNA，可在转录后调节基因表达。我们的结果显示在视网膜和玻璃体中检测到所有研究的 let-7 亚型（let-7a、let-7b、let-7c、let-7d、let-7e、let-7f 和 let-7i）。尽管大多数 let-7 成员在发育过程中在玻璃体内显着上调，但只有 let-7b、let-7c 和 let-7e 在视网膜中遵循相同的表达模式。Let-7b 和 -7c 在老化玻璃体中也增加，并表达Müller 神经胶质细胞及其细胞外囊泡在体外。此外，let-7 靶向透明质酸合成酶 2 ( Has2 ) mRNA，透明质酸合成酶。这些观察结果表明，let-7 功能在视网膜和玻璃体发育过程中很重要，并且 let-7 的同种型随着年龄的增长而增加，可能会调节透明质酸含量。