Effect of Gradually Decreasing Photoperiod on Immune Function in Siberian Hamsters

  • Yufen Tian Library, Qufu Normal University, Qufu, 273165, Shandong Province, China
  • Hanshuang Zhao College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong Province, China
  • De-Li Xu College of Life Sciences, Qufu Normal University, China
  • Mingfeng Zhao College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong Province, China
  • Qiqi Zhang College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong Province, China
  • Qiuzi Zhao College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong Province, China
  • Yanqiu Zhang College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong Province, China
  • Qilin Zhang College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong Province, China
  • Xiaokai Hu College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong Province, China
  • Zhi-Yuan Li College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong Province, China
  • Yi Wang College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong Province, China

Abstract

Animals usually use photoperiod as an important environmental cue to time the year. In terms of the winter immunocompetence enhancement hypothesis, animals in the non-tropical zone would actively enhance their immune function to decrease the negative influence of stressors such as low temperature and food shortage in winter. In the present study, we mimicked the transition from summer to winter by decreasing photoperiod gradually and examined the variations of immune repsonses in Siberian hamsters (Phodopus sungorus)  to test this hypothesis. Twenty two female adult hamsters were randomly divided into the control (12h light: 12h dark, Control, n=11) and the gradually decreasing photoperiod group (Experiment, n=11). In the experiment group, day length was decreased from 12 h: 12 h light-dark cycle to 8 h: 16 h light-dark cycle at the pace of half an hour per week. We found that gradually decreasing photoperiod had no effect on body composition (wet carcass mass, subcutaneous, retroperitoneal, mesenteric and total body fat mass) and the masses of the organs detected such as brain, heart, liver and so on in hamsters. Similarly, immunological parameters including immune organs (thymus and spleen), white blood cells and serum bacteria killing capacity indicative of innate immunity were also not influenced by gradually decreasing photoperiod, which did not support the winter immunocompetence enhancement hypothesis. However, gradually decreasing photoperiod increased phytohaemagglutinin response post-24h of PHA challenge, which supported this hypothesis. There was no correlation between cellular, innate immunity and body fat mass, suggesting that body fat was not the reasons of the changes of cellular immunity. In summary, distinct components of immune system respond to gradually decreasing photoperiod differently in Siberian hamsters.

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Published
Jul 9, 2018
How to Cite
TIAN, Yufen et al. Effect of Gradually Decreasing Photoperiod on Immune Function in Siberian Hamsters. Trends Journal of Sciences Research, [S.l.], v. 3, n. 1, p. 9, july 2018. ISSN 2377-8083. Available at: <http://tjsr.org/journal/index.php/tjsr/article/view/45>. Date accessed: 21 july 2018.