ABSTRACT
Scar formation can cause the failure of glaucoma filtration surgery. We investigated the effect of AR12286, a selective Rho-associated kinase inhibitor, on myofibroblast transdifferentiation and intraocular pressure assessment in rabbit glaucoma filtration surgery models. Cell migration and collagen contraction were used to demonstrate the functionality of AR12286-modulated human conjunctival fibroblasts (HConFs). Polymerase chain reaction quantitative analysis was used to determine the effect of AR12286 on the production of collagen Type 1A1 and fibronectin 1. Cell migration and collagen contraction in HConFs were activated by TGF-ß1. However, compared with the control group, rabbit models treated with AR12286 exhibited higher reduction in intraocular pressure after filtration surgery, and decreased collagen levels at the wound site in vivo. Therefore, increased α-SMA expression in HConFs induced by TGF-ß1 could be inhibited by AR12286, and the production of Type 1A1 collagen and fibronectin 1 in TGF-ß1-treated HConFs was inhibited by AR12286. Overall, the stimulation of HConFs by TGF-ß1 was alleviated by AR12286, and this effect was mediated by the downregulation of TGF-ß receptor-related SMAD signaling pathways. In vivo results indicated that AR12286 thus improves the outcome of filtration surgery as a result of its antifibrotic action in the bleb tissue because AR12286 inhibited the TGF-ß receptor-related signaling pathway, suppressing several downstream reactions in myofibroblast transdifferentiation.
Subject(s)
Cell Transdifferentiation/drug effects , Filtering Surgery , Glaucoma , Myofibroblasts/metabolism , Protein Kinase Inhibitors/pharmacology , Transforming Growth Factor beta/metabolism , Animals , Cell Line , Fibrosis , Glaucoma/metabolism , Glaucoma/pathology , Glaucoma/therapy , Humans , Myofibroblasts/pathology , Rabbits , Signal Transduction/drug effectsABSTRACT
The aim of this study was to investigate whether exogenous erythropoietin (EPO) administration attenuates N-methyl-D-aspartate (NMDA)-mediated excitotoxic retinal damage in Wistar rats. The survival rate of retinal ganglion cells (RGCs) were investigated by flat mount analysis and flow cytometry. A total of 125 male Wistar rats were randomly assigned to five groups: negative control, NMDA80 (i.e., 80 nmoles NMDA intravitreally injected), NMDA80 + 10ng EPO, NMDA80 + 50ng EPO, and NMDA80 + 250ng EPO. The NMDA80 + 50ng EPO treatment group was used to evaluate various administrated points (pre-/co-/post- administration of NMDA80). Meanwhile, the transferase dUTP Nick-End Labeling (TUNEL) assay of RGCs, the inner plexiform layer (IPL) thickness and the apoptotic signal transduction pathways of µ-calpain, Bax, and caspase 9 were assessed simultaneously using an immunohistochemical method (IHC). When EPO was co-administered with NMDA80, attenuated cell death occurred through the downregulation of the apoptotic indicators: µ-calpain was activated first (peak at ~18hrs), followed by Bax and caspase 9 (peak at ~40hrs). Furthermore, the images of retinal cross sections have clearly demonstrated that thickness of the inner plexiform layer (IPL) was significantly recovered at 40 hours after receiving intravitreal injection with NMDA80 and 50ng EPO. Exogenous EPO may protect RGCs and bipolar cell axon terminals in IPL by downregulating apoptotic factors to attenuate NMDA-mediated excitotoxic retinal damage.
Subject(s)
Apoptosis , Erythropoietin/pharmacology , N-Methylaspartate/pharmacology , Neuroprotective Agents/pharmacology , Retinal Ganglion Cells/drug effects , Animals , Caspase 9/genetics , Caspase 9/metabolism , Down-Regulation , Male , Rats , Rats, Wistar , Receptors, N-Methyl-D-Aspartate/agonists , Receptors, N-Methyl-D-Aspartate/metabolism , Retinal Ganglion Cells/metabolism , bcl-2-Associated X Protein/genetics , bcl-2-Associated X Protein/metabolismABSTRACT
PURPOSE: α-Lipoic acid (LA) aqueous formulations were studied for nonoral administration, including intravitreal and intraperitoneal preparations and topical eyedrops. The potential retinoprotective effects of these LA preparations were also evaluated in streptozotocin (STZ)-induced diabetic rats for screening better delivery systems of LA. METHODS: Four LA liquid preparations were prepared and investigated. The short-term accelerated stabilities of LA preparations were investigated at 3 temperatures: 50°C, 70°C, and 90°C. The time courses of LA degradation in the preparations were determined by high-performance liquid chromatography. Furthermore, the potential therapeutic effects of LA preparations in a STZ-induced diabetic rat model were assessed by vitreous fluorophotometry to evaluate the fluorescein leakage from ocular vascular vessels into the vitreous. Capillary lesion in the retina was also examined using hematoxylin-eosin-stained microsections. RESULTS: LA in an aqueous solution was rapidly degraded with the activation energy of 10.4 kcal/mol. The 3 LA preparations had shelf lives of â¼1 month at 25°C. These formulations significantly reduced the vitreous fluorescein level in STZ-induced diabetic rats as evaluated by the fluorescein leakage after tail vein injection. Capillary lesions in the retina of the diabetic rats were remarkably reduced by nonoral administration, particularly the intraperitoneal injection (30 mg/kg/day). CONCLUSIONS: LA could be developed as aqueous preparations with suitable stability for short-term use in nonoral administration. LA preparations could be administered intravitreally or intraperitoneally to reduce ocular microvascular complications, such as retinopathy, in diabetic patients.
