Propolis modulates NOS2/arginase-1 pathway in tropomyosin-induced experimental autoimmune uveitis

Abstract

In this study, we evaluated the preventive and curative effects of ethanolic extract of Propolis (EEP) during α-Tropomyosin-induced uveitis in an experimental model using Wistar rats, through the regulation of inducible nitric oxide synthase (NOS2) and arginase-1. In this context, rats received daily injection of EEP (100 mg/kg) for 5 days prior to immunization or for 9 days commencing 5 days post immunization with α-Tropomyosin extract, then were sacrificed at day 14. Histological examination, NOS2, arginase-1, and nuclear factor-κB (NF-κB) expression were evaluated in the retinas. Plasmatic production of nitric oxide (NO), urea, IL-4, and TNF-α was assessed. We have found that treatment with EEP substantially reduced the retinal histological damages induced by α-Tropomyosin. In the same context, a significant decrease of NO and TNF-α levels was noticed. Interestingly, EEP down-modulated NOS2 and NF-κB expression in retina. Also, an increase in urea and IL-4 levels was concomitant to an up-modulation of arginase-1 expression. Hence, it appears that EEP attenuated retinal damages through the induction of Th2 response and the inhibition of NF-κB/NOS2 pathway.

Beneficial Effect of Dimethyl Fumarate on Experimental Autoimmune Uveitis is Dependent of Pro-Inflammatory Markers Immunomodulation

“…As previously reported by our team, during EAU activity, a signi cant proportion of damages in ocular structures was observed and attributed mainly to nitric oxide (Djeraba et al 2010;Arroul-Lammali et al 2012;Touri et al 2019). In addition, TNF-α, has been shown to be an important cytokine involved in alteration of ocular tissue (Dick et al 2004).…”

Temperate Propolis Has Anti-Inflammatory Effects and Is a Potent Inhibitor of Nitric Oxide Formation in Macrophages

“…It is clear from the viability data and the enhancement of energy metabolites such as ATP and creatine phosphate that propolis if anything increases the viability of the cultured macrophages. The cytokine assays largely support the reports [ 3 , 4 , 5 , 6 ] that propolis is anti-inflammatory and the metabolomics data almost perfectly support the idea that propolis treatment is pushing the macrophages towards an M2-like character. The conversion of arginine to citrulline with the formation of NO is inhibited, and levels of GSH and GSSH are increased, pointing towards the promotion of activity against ROS generation; a number of intermediates required for GSH biosynthesis are elevated by propolis treatment.…”

“…In the UK, Northern Europe, and North America, propolis is collected from poplar trees and their relatives; in Southern Europe and North Africa, much of it comes from Cypress trees; and in tropical regions such as Brazil and West Africa, propolis is usually collected from many different plant sources [ 1 , 2 ]. There are numerous literature reports on the immunomodulatory effects of propolis [ 3 , 4 , 5 , 6 , 7 , 8 ]. In a recent paper, we studied several types of propolis for their effects on the metabolic response of THP-1 cells to treatment with lipopolysaccharide (LPS), and for one sample from Cameroon, which inhibited cytokine release, we studied the metabolomics of the immune response and found a clear effect of the propolis in inhibiting purine nucleotide phosphorylase [ 8 ].…”

Insight on Propolis from Mediterranean Countries: Chemical Composition, Biological Activities and Application Fields

“…Other authors have found similar results as [255] for propolis from Algeria, which showed immunomodulatory and anti-inflammatory effect in animals with uveitis induced by α-tropomyosin. [293] Mouse et al [120] did a screening of the antitumor potential of Moroccan propolis extracts, from Beni Mellal region, in P815 tumor-bearing mice and have found that the treatment with propolis have the capacity to reduce the tumor volume as compared with the control. [120] Mountassir et al [294] have investigated samples from the same region regarding its possible antinociceptive activity and have conclude that propolis activated both central and peripheral mechanisms to elicit the analgesic effect in tested animals.…”