title: Effect of melatonin on monochromatic light-induced T-lymphocyte proliferation in the thymus of chickens.
abstract: A total of 360 post-hatching day 0 (P0) Arbor Acre male broilers, including intact, sham operation and pinealectomy groups, were exposed to white light (WL), red light (RL), green light (GL) and blue light (BL) from a light-emitting diode (LED) system until for P14. We studied the effects of melatonin and its receptors on monochromatic light-induced T-lymphocyte proliferation in the thymus of broilers. The density of proliferating cell nuclear antigen (PCNA) cells and the proliferation of T-lymphocytes in response to Concanavalin A (ConA) in GL significantly increased both in vivo and in vitro (from 9.57% to 32.03% and from 34.30% to 50.53%, respectively) compared with other lights (p<0.005) and was strongly correlated with melatonin levels in plasma (p<0.005). Pinealectomy reduced the levels of circulatory melatonin and the proliferation of T-lymphocytes and eliminated the differences between GL and other lights (p<0.005). However, exogenous melatonin (10(-9)M) significantly increased the proliferative activity of T-lymphocyte by 9.64% (p=0.002). In addition, GL significantly increased mRNA expression levels of Mel1a, Mel1b and Mel1c receptors from 21.09% to 32.57%, and protein expression levels from 24.43% to 42.92% compared with RL (p<0.05). However, these effects were blocked after pinealectomy. Furthermore, 4P-PDOT (a selective Mel1b antagonist) and prazosin (a selective Mel1c antagonist) attenuated GL-induced T-lymphocyte proliferation in response to ConA (p=0.000). Luzindole (a nonselective Mel1a/Mel1b antagonist), however, did not induce these effects (p=0.334). These results suggest that melatonin may mediate GL-induced T-lymphocyte proliferation via the Mel1b and Mel1c receptors but not via the Mel1a receptor.
authors.affiliation: Laboratory of Veterinary Anatomy, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
authors.forename: Fuju
authors.initials: F
authors.lastname: Chen
authors.affiliation: Laboratory of Veterinary Anatomy, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
authors.forename: Aikebaier
authors.initials: A
authors.lastname: Reheman
authors.affiliation: Laboratory of Veterinary Anatomy, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Cao
authors.affiliation: Laboratory of Veterinary Anatomy, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
authors.forename: Zixu
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Laboratory of Veterinary Anatomy, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
authors.forename: Yulan
authors.initials: Y
authors.lastname: Dong
authors.affiliation: Department of Animal Husbandry and Veterinary, Beijing Vocational College of Agriculture, Beijing 102442, China.
authors.forename: Yuxian
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Laboratory of Veterinary Anatomy, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China. Electronic address: yxchen@cau.edu.cn.
authors.forename: Yaoxing
authors.initials: Y
authors.lastname: Chen
mesh_terms: D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects / Q000528:radiation effects*; D002478:Cells, Cultured; D002645:Chickens; D003208:Concanavalin A / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects / Q000528:radiation effects; D007150:Immunohistochemistry; D008027:Light; D008297:Male; D008550:Melatonin / Q000097:blood* / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D044094:Receptors, Melatonin / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000378:metabolism* / Q000528:radiation effects; D013764:Tetrahydronaphthalenes / Q000494:pharmacology; D013950:Thymus Gland / Q000166:cytology / Q000378:metabolism / Q000473:pathology; D014363:Tryptamines / Q000494:pharmacology
chemical_list: C114459:4-phenyl-2-propionamidotetraline; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger; D044094:Receptors, Melatonin; D013764:Tetrahydronaphthalenes; D014363:Tryptamines; D003208:Concanavalin A; C057154:luzindole; D008550:Melatonin; D011224:Prazosin
keywords: Chicken; Melatonin; Melatonin antagonists; Monochromatic light; T-lymphocyte; Thymus