by Michurina S.V. | Miroshnichenko S.M. | Ishchenko I.Yu. | Serykh A.E. | Rachkovskaya L.N.1 |
1Research Institute of Clinical and Experimental Lymphology – Branch of the Institute of Cytology and
Genetics, SB RAS, Novosibirsk, Russia | 1Research Institute of Clinical and Experimental Lymphology –
Branch of the Institute of Cytology and Genetics, SB RAS, Novosibirsk, Russia 2Research Institute of
Biochemistry – Federal Research Center for Fundamental and Translational Medicine, Novosibirsk,
Russia | 1Research Institute of Clinical and Experimental Lymphology – Branch of the Institute of
Cytology and Genetics, SB RAS, Novosibirsk, Russia | 1Research Institute of Clinical and Experimental
Lymphology – Branch of the Institute of Cytology and Genetics, SB RAS, Novosibirsk, Russia3Research
Institute of Experimental and Clinical Medicine – Federal Research Center for Fundamental and
Translational Medicine, Novosibirsk, Russia | Institute of Clinical and Experimental Lymphology – a
branch of Institute of Cytology and Genetics SB RAS, Novosibirsk, Russia;
Motivation and Aim: Prolonged continuous illumination contributes to the development of
functional pinealectomy, a decrease in adaptive cellular and humoral immune response. The
study aim was to investigate the melatonin effect on the content of young CD3low and
mature CD3hi T-lymphocyte forms in the thymus of C57Bl/6j mice with a model of functional
pinealectomy (FP).
Methods and Algorithms: Four animal groups were formed. “CL” – mice with the FP model,
which was created by keeping animals under continuous lighting (CL) for 14 days
(photoperiod light:dark 24:0 hours). “CL+MT” – animals with FP which were intragastrically
injected with melatonin (MT, 0.664 g/kg body weight) in 200μl of distilled water daily
against a background of CL. “CL+Placebo” – mice with FP which received water 200μl
intragastrically daily. “Control” – intact mice kept under standard lighting mode (14:10 h).
Immunophenotyping of CD3hi and CD3low thymocyte subpopulations was performed by
staining using CD3-ARS antibodies and analyzed using a flow cytofluorimeter. Statistical
analysis was carried out using Mann-Whitney test (“Statistica 12”).
Results: In FP mice, both a decrease in the relative number of CD3low and CD3hi
thymocytes and a significant decline in the CD3low/CD3hi ratio were found. Treatment of
animals with melatonin under CL restored the percentage of CD3low and CD3hi thymocytes,
as well as the CD3low/CD3hi ratio to control values.
Conclusion: Thus the results indicate that prolonged continuous illumination has a
depressing effect on differentiation and maturation of young thymocytes into mature forms.
Melatonin treatment in this model situation helps to compensate for the CL effects by
triggering the process of cell proliferation in the thymus from the earliest stages. This
indicates that melatonin has immunotropic properties and can be used to correct the consequences of functional pinealectomy.