Suppression of type I collagen expression by miR-29b via PI3K, Akt, and Sp1 pathway, part II: An in vivo investigation

Abstract

PURPOSE. We investigated the efficacy of miR-29b in inhibiting scar formation in rabbits who undergo glaucoma filtering surgery (GFS). METHODS. Trabeculectomy was performed on 60 rabbits diagnosed with glaucoma. The rabbits were divided into 5 groups: a blank group, single surgery group, positive control group that was treated with intraoperative mitomycin C (MMC), negative control group that was treated twice with empty vector postoperatively, and experimental group that was treated twice with Lentivirus-mediated miR-29b after being subjected to trabeculectomy. The operated eyes were tracked and followed up from postoperative days 1 to 28 (D1-D28). After the surgery, realtime PCR and Western blot analysis were performed on D28. RESULTS. At 1 week after undergoing GFS, the IOP was significantly lower in the eyes having filtering blebs. No statistically significant difference was found in the four treatment groups. After 21 days, the filtering bleb function score of the experimental group was the highest; however, their IOP was the lowest. On postoperative D28, the mean number of fibroblasts in the experimental group was significantly the lowest. The experimental group had the least collagen content according to Sircol assay. In the experimental group, the level of Col1A1 expression also was reduced in the sclera and conjunctival areas. CONCLUSIONS. A subconjunctival injection of lentivirus-mediated miR-29b lowers postoperative IOP and sustains the function of filtering bleb. It inhibits the proliferation of fibroblasts and reduces collagen deposition by repressing the PI3K/Akt/Sp1 pathway in rabbits subjected to GFS.