Protective effects of melatonin receptor agonists on endotoxin-ınduced uveitis in rats

Document Type : Original Article


1 Department of Pharmacology, Faculty of Medicine, Tekirdag Namık Kemal University, Tekirdag, Turkey

2 Department of Pharmacology, Faculty of Medicine, Kafkas University, Kars, Turkey

3 Department of Pharmacology, Faculty of Medicine, Sutcu Imam University, Kahramanmaraş, Turkey

4 Department of Pharmacology, Faculty of Medicine, Ataturk University, Erzurum, Turkey

5 Clinical Research, Development and Design Application and Research Center, Ataturk University, Erzurum, Turkey

6 Department of Ophthalmology, University of Health Science, Ümraniye Education and Research Hospital, Department of Ophthalmology, Istanbul, Turkey

7 Department of Histology and Embryology, Faculty of Medicine, Kafkas University, Kars, Turkey


Objective(s): Melatonin has an important role in regulating a variety of physiological functions of the body. We investigated the protective effects of Agomelatine (AGO) and Ramelteon (RAME) on Endotoxin-Induced Uveitis (EIU) in rats.
Materials and Methods: 70 rats were randomly divided into fourteen groups. Healthy group )normal saline, IP(, Uveitis group (200  μg/kg lipopolysaccharide (LPS), SC), DEX group (200  μg/kg LPS plus 1  mg/kg dexamethasone, IP), AGO20 group received 200 μg/kg LPS plus 20 mg/kg AGO, AGO40 group received 200  μg/kg LPS plus 40  mg/kg AGO, RAME2 group received 200 μg/kg LPS plus 2  mg/kg RAME, and group RAME4 received 200 μg/kg LPS plus 4 mg/kg RAME. Each group had two subgroups: the 3rd and 24th hour. The eye tissues were collected and investigated biomicroscopically (clinical manifestations and scoring, molecularly(qRT-PCR analyses of Tumor Necrosis Factor-α (TNF-α), vascular endothelial growth factor(VEGF), and Caspase 3 and Caspase 9 mRNA expression), biochemically (Superoxide dismutase activity, Glutathione, and Malondialdehyde levels) and histopathologically (staining with Harris Hematoxylin and Eosin Y).
Results: Melatonin receptor agonist treatment reduced the clinical score count of ocular inflammation in the uveitic rats. TNF-α, VEGF, Caspase 9, and Caspase 3 levels markedly decreased in the uveitic rats. Melatonin receptor agonists significantly ameliorated fixed changes in GSH, SOD, and MDA levels. Melatonin receptor agonists also ameliorated histopathological injury in eye tissues associated with uveitis.
Conclusion: Melatonin receptor agonists ameliorated the inflammatory response in EIU. These findings suggest that melatonin receptor agonists may represent a potential novel therapeutic drug for uveitis treatment.


1. Guly CM, Forrester JV. Investigation and management of uveitis. BMJ 2010;341:c4976.
2. Seve P, Cacoub P, Bodaghi B, Trad S, Sellam J, Bellocq D, et al. Uveitis: Diagnostic work-up. A literature review and recommendations from an expert committee. Autoimmun Rev 2017;16:1254-1264.
3. Suttorp-Schulten MS, Rothova A. The possible impact of uveitis in blindness: a literature survey. Br J Ophthalmol 1996;80:844-848.
4. Tsubura A, Lai YC, Miki H, Sasaki T, Uehara N, Yuri T, et al. Animal models of N-Methyl-N-nitrosourea-induced mammary cancer and retinal degeneration with special emphasis on therapeutic trials. In Vivo 2011;25:11-22.
5. Tosini G, Baba K, Hwang CK, Iuvone PM. Melatonin: An underappreciated player in retinal physiology and pathophysiology. Exp Eye Res 2012;103:82-89.
6. Miyamoto M. Pharmacology of ramelteon, a selective MT1/MT2 receptor agonist: a novel therapeutic drug for sleep disorders. CNS Neurosci Ther 2009;15:32-51.
7. Srinivasan V, Kaur C, Pandi-Perumal S, Brown GM, Cardinali DP. Melatonin and its agonist ramelteon in Alzheimer’s disease: possible therapeutic value. Int J Alzheimers Dis 2010;2011:741974.
8. Shimizu N, Nozawa M, Sugimoto K, Yamamoto Y, Minami T, Hayashi T, et al. Therapeutic efficacy and anti-inflammatory effect of ramelteon in patients with insomnia associated with lower urinary tract symptoms. Res Rep Urol 2013;5:113-119.
9. Yao K, Zhao YF, Zu HB. Melatonin receptor stimulation by agomelatine prevents Abeta-induced tau phosphorylation and oxidative damage in PC12 cells. Drug Des Devel Ther 2019;13:387-396.
10. Yadav UC, Subramanyam S, Ramana KV. Prevention of endotoxin-induced uveitis in rats by benfotiamine, a lipophilic analogue of vitamin B1. Invest Ophthalmol Vis Sci 2009;50:2276-2282.
11. Savran M, Aslankoc R, Ozmen O, Erzurumlu Y, Savas HB, Temel EN, et al. Agomelatine could prevent brain and cerebellum injury against LPS-induced neuroinflammation in rats. Cytokine 2020;127:154957.
12. Ozmen O, Topsakal S. Preventive effect of agomelatine in lipopolysaccharide-induced pancreatic pathology. Drug Chem Toxicol 2022;45:180-184.
13. Wu XL, Lu SS, Liu MR, Tang WD, Chen JZ, Zheng YR, et al. Melatonin receptor agonist ramelteon attenuates mouse acute and chronic ischemic brain injury. Acta Pharmacol Sin 2020;41:1016-1024.
14. Keles S, Halici Z, Atmaca HT, Yayla M, Yildirim K, Ekinci M, et al. The ocular endothelin system: A novel target for the treatment of endotoxin-induced uveitis with bosentan. Invest Ophthalmol Vis Sci 2014;55:3517-3524.
15. Chang YH, Horng CT, Chen YH, Chen PL, Chen CL, Liang CM, et al. Inhibitory effects of glucosamine on endotoxin-induced uveitis in Lewis rats. Invest Ophthalmol Vis Sci 2008;49:5441-5449.
16. Rosenbaum JT, McDevitt HO, Guss RB, Egbert PR. Endotoxin-induced uveitis in rats as a model for human disease. Nature 1980;286:611-613.
17. Pouvreau I, Zech JC, Thillaye-Goldenberg B, Naud MC, Van Rooijen N, de Kozak Y. Effect of macrophage depletion by liposomes containing dichloromethylene-diphosphonate on endotoxin-induced uveitis. J Neuroimmunol 1998;86:171-181.
18. Bozkurt E, Muhafiz E, Sengul D, Ucak T, Atum M. Can the CRP/albumin Ratio be Used as a New Indicator of Activation in Patients with Uveitis? Ocul Immunol Inflamm 2021;29:1017-1022.
19. Livak KJ, Schmittgen TD. Analysis of relative gene expression data using real-time quantitative PCR and the 2(-Delta Delta C(T)) Method. Methods 2001;25:402-408.
20. Sun Y, Oberley LW, Li Y. A simple method for clinical assay of superoxide dismutase. Clin Chem 1988;34:497-500.
21. Sedlak J, Lindsay RH. Estimation of total, protein-bound, and nonprotein sulfhydryl groups in tissue with Ellman’s reagent. Anal Biochem 1968;25:192-205.
22. Ohkawa H, Ohishi N, Yagi K. Assay for lipid peroxides in animal tissues by thiobarbituric acid reaction. Anal Biochem 1979;95:351-358.
23. Bayir Y, Un H, Cadirci E, Akpinar E, Diyarbakir B, Calik I, et al. Effects of aliskiren, an RAAS inhibitor, on a carrageenan-induced pleurisy model of rats. An Acad Bras Cienc 2019;91:e20180106.
24. Palabiyik SS, Karakus E, Akpinar E, Halici Z, Bayir Y, Yayla M, et al. The role of urotensin receptors in the paracetamol-induced hepatotoxicity model in mice: Ameliorative potential of urotensin II Antagonist. Basic Clin Pharmacol Toxicol 2016;118:150-159.
25. Tatar A, Yayla M, Kose D, Halici Z, Yoruk O, Polat E. The role of endothelin-1 and endothelin receptor antagonists in allergic rhinitis inflammation: Ovalbumin-induced rat model. Rhinology 2016;54:266-272.
26. Un H, Ugan RA, Kose D, Yayla M, Tastan TB, Bayir Y, et al. A new approach to sepsis treatment by rasagiline: A molecular, biochemical and histopathological study. Mol Biol Rep 2022; 49:3875-3883.
27. Dick AD, Tundia N, Sorg R, Zhao C, Chao J, Joshi A, et al. Risk of ocular complications in patients with noninfectious intermediate uveitis, posterior uveitis, or panuveitis. Ophthalmology 2016;123:655-662.
28. Patel AK, Newcomb CW, Liesegang TL, Pujari SS, Suhler EB, Thorne JE, et al. Risk of retinal neovascularization in cases of uveitis. Ophthalmology 2016;123:646-654.
29. Fanlo P, Heras H, Espinosa G, Adan A. Complications and visual acuity of patients with uveitis: Epidemiological study in a reference unit in northern Spain. Arch Soc Esp Oftalmol (Engl Ed) 2019;94:419-425.
30. Touitou Y, Le Hoang P, Claustrat B, Attye T, Auzeby A, Brun J, et al. Decreased nocturnal plasma melatonin peak in patients with a functional alteration of the retina in relation with uveitis. Neurosci Lett 1986;70:170-174.
31. Abe T, Tamada H, Koizumi T, Nakajima A, Satoh N, Sakuragi S. Decreased serum melatonin levels in rats with experimental autoimmune uveitis/pinealitis and in patients with uveitis. Ocul Immunol Inflamm 1996;4:175-182.
32. Stonex T, Salmon JH, Adler KB, Gilger BC. Peptide Inhibitors of MARCKS Suppress Endotoxin Induced Uveitis in Rats. J Ocul Pharmacol Ther 2022;38:223-231.
33. Zhang N, Yu S, Liu XL, Lu H. Low dose of lipopolysaccharide pretreatment preventing subsequent endotoxin-induced uveitis is associated with PI3K/AKT pathway. J Immunol Res 2017;2017: 1273940.
34. Kim EY, Moudgil KD. Regulation of autoimmune inflammation by pro-inflammatory cytokines. Immunol Lett 2008;120:1-5.
35. Mok CC. The Jakinibs in systemic lupus erythematosus: Progress and prospects. Expert Opin Investig Drugs 2019;28:85-92.
36. Ahmad SF, Ansari MA, Zoheir KM, Bakheet SA, Korashy HM, Nadeem A, et al. Regulation of TNF-alpha and NF-kappaB activation through the JAK/STAT signaling pathway downstream of histamine 4 receptor in a rat model of LPS-induced joint inflammation. Immunobiology 2015;220:889-898.
37. Carrillo-Vico A, Lardone PJ, Alvarez-Sanchez N, Rodriguez-Rodriguez A, Guerrero JM. Melatonin: Buffering the immune system. Int J Mol Sci 2013;14:8638-8683.
38. Xu L, Zhang W, Kwak M, Zhang LJ, Lee PCW, Jin JO. Protective effect of melatonin against polymicrobial sepsis is mediated by the anti-bacterial effect of neutrophils. Front Immunol 2019;10:1371.
39. Duan WX, Yang Y, Yi W, Yan JJ, Liang ZX, Wang N, et al. New role of JAK2/STAT3 signaling in endothelial cell oxidative stress injury and protective effect of melatonin. PLoS One 2013;8: e57941.
40. Liang WC, Ren JL, Yu QX, Li J, Ng TK, Chu WK, et al. Signaling mechanisms of growth hormone-releasing hormone receptor in LPS-induced acute ocular inflammation. P Natl Acad Sci USA 2020;117:6067-6074.
41. Yuan Z, Chen X, Yang W, Lou B, Ye N, Liu Y. The anti-inflammatory effect of minocycline on endotoxin-induced uveitis and retinal inflammation in rats. Mol Vis 2019;25:359-372.
42. Celinski K, Konurek PC, Slomka M, Cichoz-Lach H, Brzozowski T, Konturek SJ, et al. Effects of treatment with melatonin and tryptophan on liver enzymes, parametrs of fat metabolism and plasma levels of cytokines in patients with non-alcoholic fatty liver disease-14 months follow up. J Physiol Pharmacol 2014;65:75-82.
43. Famiglietti EV, Stopa EG, McGookin ED, Song P, LeBlanc V, Streeten BW. Immunocytochemical localization of vascular endothelial growth factor in neurons and glial cells of human retina. Brain Res 2003;969:195-204.
44. Do JY, Choi YK, Kook H, Suk K, Lee IK, Park DH. Retinal hypoxia induces vascular endothelial growth factor through induction of estrogen-related receptor gamma. Biochem Biophys Res Commun 2015;460:457-463.
45. Simsek M, Cakar Ozdal P, Akbiyik F, Citirik M, Berker N, Ozdamar Erol Y, et al. Aqueous humor IL-8, IL-10, and VEGF levels in Fuchs’ uveitis syndrome and Behcet’s uveitis. Int Ophthalmol 2019;39:2629-2636.
46. Doganlar ZB, Doganlar O, Kurtdere K, Guclu H, Chasan T, Turgut E. Melatonin prevents blood-retinal barrier breakdown and mitochondrial dysfunction in high glucose and hypoxia-induced in vitro diabetic macular edema model. Toxicol In Vitro 2021;75:105191.
47. Doganlar ZB, Guclu H, Oztopuz O, Turkon H, Dogan A, Uzun M, et al. The role of melatonin in oxidative stress, DNA damage, apoptosis and angiogenesis in fetal eye under preeclampsia and melatonin deficiency stress. Curr Eye Res 2019;44:1157-1169.
48. Chang YS, Lin CF, Wu CL, Kuo PY, Wu FS, Shieh CC, et al. Mechanisms underlying benzyl alcohol cytotoxicity (triamcinolone acetonide preservative) in human retinal pigment epithelial cells. Invest Ophthalmol Vis Sci 2011;52:4214-4222.
49. Jha P, Matta B, Lyzogubov V, Tytarenko R, Bora PS, Bora NS. Crucial role of apoptosis in the resolution of experimental autoimmune anterior uveitis. Invest Ophthalmol Vis Sci 2007;48:5091-5100.
50. Xu J, Chen P, Zhao G, Wei S, Li Q, Guo C, et al. Copolymer micelle-administered melatonin ameliorates hyperosmolarity-induced ocular surface damage through regulating pink1-mediated mitophagy. Curr Eye Res 2022:1-16.
51. Zhai M, Li B, Duan W, Jing L, Zhang B, Zhang M, et al. Melatonin ameliorates myocardial ischemia reperfusion injury through SIRT3-dependent regulation of oxidative stress and apoptosis. J Pineal Res 2017;63:e12419.
52. Ozsimsek A, Naziroglu M. The involvement of TRPV4 on the hypoxia-induced oxidative neurotoxicity and apoptosis in a neuronal cell line: Protective role of melatonin. Neurotoxicology 2021;87:136-148.
53.Yadav UC, Kalariya NM, Ramana KV. Emerging role of anti-oxidants in the protection of uveitis complications. Curr Med Chem 2011;18:931-942.
54. Satici A, Guzey M, Gurler B, Vural H, Gurkan T. Malondialdehyde and anti-oxidant enzyme levels in the aqueous humor of rabbits in endotoxin-induced uveitis. Eur J Ophthalmol 2003;13:779-7783.
55. Yang GG, Yu LZ, Jiang SM, Zhu JF. Melatonin antagonizes oxidative stress-induced mitochondrial dysfunction in retinal pigmented epithelium cells via melatonin receptor 1 (MT1). J Toxicol Sci 2018;43:659-669.
56. Sanchez-Barcelo EJ, Mediavilla MD, Vriend J, Reiter RJ. Constitutive photomorphogenesis protein 1 (COP1) and COP9 signalosome, evolutionarily conserved photomorphogenic proteins as possible targets of melatonin. J Pineal Res 2016;61:41-51.
57. He R, Cui M, Lin H, Zhao L, Wang J, Chen S, et al. Melatonin resists oxidative stress-induced apoptosis in nucleus pulposus cells. Life Sci 2018;199:122-130.
58. Moniruzzaman M, Ghosal I, Das D, Chakraborty SB. Melatonin ameliorates H2O2-induced oxidative stress through modulation of Erk/Akt/NFkB pathway. Biol Res 2018;51:17.
59. Labsi M, Soufli I, Belguendouz H, Djebbara S, Hannachi L, Amir ZC, et al. Beneficial effect of dimethyl fumarate on experimental autoimmune uveitis is dependent of pro-inflammatory markers immunomodulation. Inflammopharmacology 2021;29:1389-1398.
60. Garcia-Otero X, Mondelo-Garcia C, Gonzalez F, Perez-Fernandez R, Avila L, Antunez-Lopez JR, et al. Anti-inflammatory effect of tacrolimus/hydroxypropyl-beta-cyclodextrin eye drops in an endotoxin-induced uveitis model. Pharmaceutics 2021;13: 1737.
61. Crabtree E, Uribe K, Smith SM, Roberts D, Salmon JH, Bower JJ, et al. Inhibition of experimental autoimmune uveitis by intravitreal AAV-Equine-IL10 gene therapy. PLoS One 2022;17:e0270972.