(1) Background: Glaucoma is a multifactorial group of diseases characterized by progressive optic neuropathy. Intraocular pressure (IOP) is the only successfully modifiable risk factor for all forms of glaucoma. However, recent research has highlighted the reduction of oxidative stress and neuroinflammation as promising therapeutic targets. In this study, we evaluated the antiglaucomatous effects of a combined herbal extract applied as eye drops in a rat model of glaucoma. (2) Methods: Sprague Dawley rats were divided into four groups: healthy controls, glaucomatous animals treated with preservative-free artificial tears, and healthy and glaucomatous groups receiving combined herbal-based eye drops for 8 weeks. Glaucoma was induced through injection of microbeads into the anterior chamber at week 1 and week 3. Before the first injection and at weeks 4 and 8, rats underwent optical coherence tomography (OCT) and electroretinogram (ERG) recordings. Retinal analyses were conducted to assess retinal ganglion cell (RGC) count, vessel density, and markers of neural pathways, oxidative stress, and inflammation. (3) Results: The combination of herbal extracts showed beneficial effects on IOP elevation, and significantly improved ERG responses. Neuroprotective effects were assessed using OCT, immunohistochemistry, and proteomics. Most parameters in herbal eye drop-treated rats were not statistically different from those in healthy controls. (4) Conclusions: Topical administration of plant-based compounds may serve as an effective supportive therapy for ocular hypertension and retinal neuroprotection.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide exerting, among others, strong trophic and protective effects. It plays a role in several physiological functions, including glucose homeostasis. The protective effects of PACAP are mainly mediated via its specific PAC1 receptor by stimulating anti-inflammatory, anti-apoptotic and antioxidant pathways. The aim of the present review is to summarize data on the protective effects of PACAP in the three major complications of diabetes, retinopathy, nephropathy and neuropathy, as well as some other complications. In type 1 and type 2 diabetic retinopathy models and in glucose-exposed cells of the eye, PACAP counteracted the degeneration of retinal layers and inhibited apoptosis and factors leading to abnormal vessel growth. In models of nephropathy, kidney morphology was better retained after PACAP administration, with decreased apoptosis and fibrosis. In diabetic neuropathy, PACAP protected against axonal–myelin lesions and less activation in pain processing centers. This neuropeptide has several other beneficial effects in diabetes-induced complications like altered vascular response, cognitive deficits and atherosclerosis. The promising therapeutic effects of PACAP in several pathological conditions have encouraged researchers to design PACAP-related drugs and to develop ways to enhance tissue delivery. These intentions are expected to result in overcoming the hurdles preventing PACAP from being introduced into therapeutic treatments, including diabetes-related conditions.

The prevalence of hypoxia-caused eye diseases is increasing, but effective, non-invasive treatment options are not available. Abscisic acid (ABA) is a plant hormone with anti-inflammatory and antioxidant effects. ABA is also present in various mammalian tissues and plays an important role in metabolic processes. Therefore, we aimed to investigate the potential protective role of ABA eye drops in ischemic retinopathy. Retinal ischemia was induced by permanent unilateral common carotid artery occlusion (UCCAO) in mice. Half of the animals received ABA eye drops two times a day for two weeks. Optical coherence tomography (OCT) was used to follow the changes in retinal thickness. Moreover, immunohistochemistry and molecular biology methods were used to explore the morphological changes and the underlying mechanisms, respectively. Based on OCT measurements, ischemic retinopathy was successfully developed. The decrease in the thickness of numerous retinal layers could be prevented with ABA eye drops. The ganglion cell number decreased significantly after UCCAO in the central and peripheral regions of the retina. ABA treatment could moderate the damage in both regions. Furthermore, our apoptosis array results suggest that ABA regulates the apoptotic pathways under hypoxic conditions. In conclusion, ABA eye drops may represent a new potential therapeutic option for the treatment of ischemic retinopathy.