Purpose
To examine the expression of Angiotensin II (Ang II) and type I, type II receptors (AT1, AT2) in Tenon's capsule fibroblasts after rabbit trabeculectomy, and to investigate the role of Ang II in human Tenon's capsule fibroblasts (HTFs) proliferation, migration, phenotype transition and extracellular matrix (ECM) synthesis.
Methods
1. In Vivo: We performed trabeculectomy on rabbit eyes and used immunohistochemical staining to investigate protein expression of Ang II, AT1 and AT2 in Tenon's capsule fibroblasts. 2. In Vitro: HTFs were obtained from patients during cataract surgery and treated with increasing concentrations of Ang II from 10-10M to 10-5M, transforming growth factor β1 (TGF-β1) (10ng/mL) and vehicle as control. Cell proliferation was investigated by CCK-8 assay, migration by wound healing assay and transwell assay. Protein expression of alpha smooth muscle actin (α-SMA) and Collagen I (Col I) were measured by western blot and immunofluorescence. Statistical significance was assumed if P<0.05.
Results
In animal models, the expression of Ang II and AT1 increased from day 1 after surgery while AT2 increased from day 7. In cultured HTFs, Ang II promoted cell proliferation. The most robust cell proliferation was observed between concentrations of 10-9M and 10-7M of Ang II (P<0.05). In terms of cell migration and phenotype transition to myofibroblasts(MFs), low concentration of Ang II (10-8M) was more effective than high concentration (10-5M) (P<0.05). In addition, Ang II markedly induced α-SMA, protein expressed by MFs, and Col I expression. Stimulation with angiotensin II (between 10-9M and 10-7M) for around 2 to 3 days caused maximum protein expression.
Conclusions
Our results suggest that Ang II increases HTFs proliferation, migration and phenotype transition, causing wound healing after trabeculectomy in vivo and in vitro.
Keywords: 765 wound healing •
512 EMT (epithelial mesenchymal transition) •
474 conjunctiva