FREE SHIPPING over $40
OVER 10000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
Animals : an open access journal from MDPI2023; 13(14); doi: 10.3390/ani13142335

Optimised Stable Lighting Strengthens Circadian Clock Gene Rhythmicity in Equine Hair Follicles.

Abstract: Hair follicles (HF) represent a useful tissue for monitoring the circadian clock in mammals. Irregular light exposure causes circadian disruption and represents a welfare concern for stabled horses. We aimed to evaluate the impact of two stable lighting regimes on circadian clock gene rhythmicity in HF from racehorses. Two groups of five Thoroughbred racehorses in training at a commercial racehorse yard were exposed to standard incandescent light or a customized LED lighting system. The control group received light from incandescent bulbs used according to standard yard practice. The treatment group received timed, blue-enriched white LED light by day and dim red LED light at night. On weeks 0 and 20, mane hairs were collected at 4 h intervals for 24 h. Samples were stored in RNAlater at -20 °C. RNA was isolated and samples interrogated by quantitative PCR for the core clock genes: ARNTL, CRY1, PER1, PER2, NR1D2, and the clock-controlled gene DBP. Cosinor analyses revealed 24 h rhythmicity for NR1D2 and PER2 and approached significance for CRY1 (p = 0.013, p = 0.013, and p = 0.051, respectively) in week 20 in the treatment group only. No rhythmicity was detected in week 0 or in week 20 in the HF of control horses. Results suggest that lighting practices in racehorse stables may be improved to better stimulate optimum functioning of the circadian system.
Get Full Text
Publication Date: 2023-07-17 PubMed ID: 37508112PubMed Central: PMC10376498DOI: 10.3390/ani13142335Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
LinkedInCopy
  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research study aims to analyze the effects of different stable lighting regimes on the circadian rhythm of racehorses. It indicates that customized LED lighting, comprising both blue-enriched white light during the day and dim red light at night, notably enhances the rhythmicity of certain ‘clock genes’ in horses.

Objectives & Methodology

  • The main goal of the research was to scrutinize the influence of two disparate stable lighting systems on the rhythmicity of circadian clock genes in the hair follicles of racehorses.
  • Two groups of five thoroughbred racehorses were selected for the study, and they were trained at a commercial racehorse yard. One group was exposed to standard incandescent light while the other experienced a personalized LED lighting system.
  • The incandescent light group mirrored the typical yard practices while the LED group was exposed to timed, blue-tinted white LED light during the day and dimmed red LED light at night.
  • To gauge the impact on the circadian clock genes, mane hairs from the horses were collected every 4 hours over the course of 24 hours at the start (0 week) and end (20 weeks) of the experiment.
  • The genes related to the circadian clock (ARNTL, CRY1, PER1, PER2, NR1D2), and a clock-controlled gene DBP were monitored using quantitative PCR in the isolated RNA samples.

Findings & Conclusions

  • Interestingly, 24-hour rhythmicity for NR1D2 and PER2 was detected in the LED light-exposed group in the 20th week of the trial and almost reached statistical significance for CRY1.
  • The rhythmicity of these genes was not observed in either week 0 or week 20 in the control horses who were exposed to standard incandescent light.
  • The results thus hint at the fact that altered stable lighting practices, particularly the use of a timed, color-adjusted LED lighting system, can stimulate an optimum function of the circadian system in racehorses.
  • This study offers insights into how lighting environmental modifications (>can potentially impact animal welfare, enhance their physiological regulation, and possibly, performance).

Cite This Article

APA
Collery A, Browne JA, O'Brien C, Sheridan JT, Murphy BA. (2023). Optimised Stable Lighting Strengthens Circadian Clock Gene Rhythmicity in Equine Hair Follicles. Animals (Basel), 13(14). https://doi.org/10.3390/ani13142335

Publication

Animals : an open access journal from MDPI
ISSN: 2076-2615
NlmUniqueID: 101635614
Country: Switzerland
Language: English
Volume: 13
Issue: 14

Researcher Affiliations

Collery, Aileen
  • School of Agriculture and Food Science, University College Dublin, Belfield, D04 V1W8 Dublin, Co. Dublin, Ireland.
Browne, John A
  • School of Agriculture and Food Science, University College Dublin, Belfield, D04 V1W8 Dublin, Co. Dublin, Ireland.
O'Brien, Christiane
  • Equilume Ltd., W91 TP22 Naas, Co. Kildare, Ireland.
Sheridan, John T
  • School of Electrical, Electronic and Mechanical Engineering, University College Dublin, Belfield, D04 V1W8 Dublin, Co. Dublin, Ireland.
Murphy, Barbara A
  • School of Agriculture and Food Science, University College Dublin, Belfield, D04 V1W8 Dublin, Co. Dublin, Ireland.

Grant Funding

  • n/a / Irish Research Council Enterprise Partnership Scheme Postgraduate Scholarship
  • n/a / Equilume Ltd

Conflict of Interest Statement

B.A. Murphy and J.T. Sheridan (recently deceased) are cofounders of Equilume Ltd., a spin-out company deriving from their research at University College Dublin, and are members of the company’s Board of Directors. C. O’Brien was an employee of Equilume Ltd. at the time of the study. None of the authors have any other financial or personal relationships that could inappropriately influence or bias the content of the paper.

References

This article includes 68 references
  1. Reppert SM, Weaver DR. Coordination of circadian timing in mammals.. Nature 2002 Aug 29;418(6901):935-41.
    doi: 10.1038/nature00965pubmed: 12198538google scholar: lookup
  2. Albrecht U. Timing to perfection: the biology of central and peripheral circadian clocks.. Neuron 2012 Apr 26;74(2):246-60.
    doi: 10.1016/j.neuron.2012.04.006pubmed: 22542179google scholar: lookup
  3. Bedrosian TA, Nelson RJ. Timing of light exposure affects mood and brain circuits.. Transl Psychiatry 2017 Jan 31;7(1):e1017.
    doi: 10.1038/tp.2016.262pmc: PMC5299389pubmed: 28140399google scholar: lookup
  4. Lowrey PL, Takahashi JS. Mammalian circadian biology: elucidating genome-wide levels of temporal organization.. Annu Rev Genomics Hum Genet 2004;5:407-41.
    doi: 10.1146/annurev.genom.5.061903.175925pmc: PMC3770722pubmed: 15485355google scholar: lookup
  5. Richards J, Gumz ML. Advances in understanding the peripheral circadian clocks.. FASEB J 2012 Sep;26(9):3602-13.
    doi: 10.1096/fj.12-203554pmc: PMC3425819pubmed: 22661008google scholar: lookup
  6. Yamazaki S, Numano R, Abe M, Hida A, Takahashi R, Ueda M, Block GD, Sakaki Y, Menaker M, Tei H. Resetting central and peripheral circadian oscillators in transgenic rats.. Science 2000 Apr 28;288(5466):682-5.
    doi: 10.1126/science.288.5466.682pubmed: 10784453google scholar: lookup
  7. Geyfman M, Andersen B. How the skin can tell time.. J Invest Dermatol 2009 May;129(5):1063-6.
    doi: 10.1038/jid.2008.384pubmed: 19369933google scholar: lookup
  8. Yoo SH, Yamazaki S, Lowrey PL, Shimomura K, Ko CH, Buhr ED, Siepka SM, Hong HK, Oh WJ, Yoo OJ, Menaker M, Takahashi JS. PERIOD2::LUCIFERASE real-time reporting of circadian dynamics reveals persistent circadian oscillations in mouse peripheral tissues.. Proc Natl Acad Sci U S A 2004 Apr 13;101(15):5339-46.
    doi: 10.1073/pnas.0308709101pmc: PMC397382pubmed: 14963227google scholar: lookup
  9. Murphy BA, Vick MM, Sessions DR, Cook RF, Fitzgerald BP. Evidence of an oscillating peripheral clock in an equine fibroblast cell line and adipose tissue but not in peripheral blood.. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2006 Jul;192(7):743-51.
    doi: 10.1007/s00359-006-0108-7pubmed: 16479406google scholar: lookup
  10. Martin AM, Elliott JA, Duffy P, Blake CM, Ben Attia S, Katz LM, Browne JA, Gath V, McGivney BA, Hill EW, Murphy BA. Circadian regulation of locomotor activity and skeletal muscle gene expression in the horse.. J Appl Physiol (1985) 2010 Nov;109(5):1328-36.
    doi: 10.1152/japplphysiol.01327.2009pubmed: 20847133google scholar: lookup
  11. Watts LM, Browne JA, Murphy BA. Investigation of a non-invasive method of assessing the equine circadian clock using hair follicle cells.. J Circadian Rhythms 2012 Oct 5;10(1):7.
    doi: 10.1186/1740-3391-10-7pmc: PMC3514281pubmed: 23039139google scholar: lookup
  12. Giannetto C, Cannella V, Giudice E, Guercio A, Piccione G. Behavioral and physiological processes in horses and their linkage with peripheral clock gene expression: A preliminary study. J. Vet. Behav. 2019;34:37–41.
    doi: 10.1016/j.jveb.2019.08.004google scholar: lookup
  13. Giannetto C, Fazio F, Alberghina D, Giudice E, Piccione G. Clock Genes Expression in Peripheral Leukocytes and Plasma Melatonin Daily Rhythm in Horses.. J Equine Vet Sci 2020 Jan;84:102856.
    doi: 10.1016/j.jevs.2019.102856pubmed: 31864454google scholar: lookup
  14. Giannetto C, Fazio F, Giudice E, Mazzullo G, Piccione G. Physiological role of circadian clock gene on the energetic me-tabolism in horses. J. Vet. Behav. 2022;47:29–34.
    doi: 10.1016/j.jveb.2021.10.002google scholar: lookup
  15. Brainard GC, Sliney D, Hanifin JP, Glickman G, Byrne B, Greeson JM, Jasser S, Gerner E, Rollag MD. Sensitivity of the human circadian system to short-wavelength (420-nm) light.. J Biol Rhythms 2008 Oct;23(5):379-86.
    doi: 10.1177/0748730408323089pubmed: 18838601google scholar: lookup
  16. Berson DM, Dunn FA, Takao M. Phototransduction by retinal ganglion cells that set the circadian clock.. Science 2002 Feb 8;295(5557):1070-3.
    doi: 10.1126/science.1067262pubmed: 11834835google scholar: lookup
  17. Hattar S, Liao HW, Takao M, Berson DM, Yau KW. Melanopsin-containing retinal ganglion cells: architecture, projections, and intrinsic photosensitivity.. Science 2002 Feb 8;295(5557):1065-70.
    doi: 10.1126/science.1069609pmc: PMC2885915pubmed: 11834834google scholar: lookup
  18. Brainard GC, Hanifin JP, Greeson JM, Byrne B, Glickman G, Gerner E, Rollag MD. Action spectrum for melatonin regulation in humans: evidence for a novel circadian photoreceptor.. J Neurosci 2001 Aug 15;21(16):6405-12.
    doi: 10.1523/JNEUROSCI.21-16-06405.2001pmc: PMC6763155pubmed: 11487664google scholar: lookup
  19. Pevet P, Challet E. Melatonin: both master clock output and internal time-giver in the circadian clocks network.. J Physiol Paris 2011 Dec;105(4-6):170-82.
    doi: 10.1016/j.jphysparis.2011.07.001pubmed: 21914478google scholar: lookup
  20. Walsh CM, Prendergast RL, Sheridan JT, Murphy BA. Blue light from light-emitting diodes directed at a single eye elicits a dose-dependent suppression of melatonin in horses.. Vet J 2013 May;196(2):231-5.
    doi: 10.1016/j.tvjl.2012.09.003pubmed: 23079244google scholar: lookup
  21. Murphy BA, Walsh CM, Woodward EM, Prendergast RL, Ryle JP, Fallon LH, Troedsson MH. Blue light from individual light masks directed at a single eye advances the breeding season in mares.. Equine Vet J 2014 Sep;46(5):601-5.
    doi: 10.1111/evj.12153pubmed: 23909505google scholar: lookup
  22. Bedrosian TA, Vaughn CA, Galan A, Daye G, Weil ZM, Nelson RJ. Nocturnal light exposure impairs affective responses in a wavelength-dependent manner.. J Neurosci 2013 Aug 7;33(32):13081-7.
    doi: 10.1523/JNEUROSCI.5734-12.2013pmc: PMC6619722pubmed: 23926261google scholar: lookup
  23. Lockley SW, Gooley JJ. Circadian photoreception: spotlight on the brain.. Curr Biol 2006 Sep 19;16(18):R795-7.
    doi: 10.1016/j.cub.2006.08.039pubmed: 16979545google scholar: lookup
  24. Stenvers DJ, van Dorp R, Foppen E, Mendoza J, Opperhuizen AL, Fliers E, Bisschop PH, Meijer JH, Kalsbeek A, Deboer T. Dim light at night disturbs the daily sleep-wake cycle in the rat.. Sci Rep 2016 Oct 20;6:35662.
    doi: 10.1038/srep35662pmc: PMC5071835pubmed: 27762290google scholar: lookup
  25. Zhang Z, Wang HJ, Wang DR, Qu WM, Huang ZL. Red light at intensities above 10 lx alters sleep-wake behavior in mice.. Light Sci Appl 2017 May;6(5):e16231.
    doi: 10.1038/lsa.2016.231pmc: PMC6062196pubmed: 30167247google scholar: lookup
  26. Opperhuizen AL, Stenvers DJ, Jansen RD, Foppen E, Fliers E, Kalsbeek A. Light at night acutely impairs glucose tolerance in a time-, intensity- and wavelength-dependent manner in rats.. Diabetologia 2017 Jul;60(7):1333-1343.
    doi: 10.1007/s00125-017-4262-ypmc: PMC5487588pubmed: 28374068google scholar: lookup
  27. Higuchi S, Fukuda T, Kozaki T, Takahashi M, Miura N. Effectiveness of a red-visor cap for preventing light-induced melatonin suppression during simulated night work.. J Physiol Anthropol 2011;30(6):251-8.
    doi: 10.2114/jpa2.30.251pubmed: 22197958google scholar: lookup
  28. Murphy BA, O'Brien C, Elliott JA. Red light at night permits the nocturnal rise of melatonin production in horses.. Vet J 2019 Oct;252:105360.
    doi: 10.1016/j.tvjl.2019.105360pubmed: 31554596google scholar: lookup
  29. Sakamoto K, Nagase T, Fukui H, Horikawa K, Okada T, Tanaka H, Sato K, Miyake Y, Ohara O, Kako K, Ishida N. Multitissue circadian expression of rat period homolog (rPer2) mRNA is governed by the mammalian circadian clock, the suprachiasmatic nucleus in the brain.. J Biol Chem 1998 Oct 16;273(42):27039-42.
    doi: 10.1074/jbc.273.42.27039pubmed: 9765215google scholar: lookup
  30. Fonken LK, Aubrecht TG, Meléndez-Fernández OH, Weil ZM, Nelson RJ. Dim light at night disrupts molecular circadian rhythms and increases body weight.. J Biol Rhythms 2013 Aug;28(4):262-71.
    doi: 10.1177/0748730413493862pmc: PMC4033305pubmed: 23929553google scholar: lookup
  31. Polidarová L, Sládek M, Soták M, Pácha J, Sumová A. Hepatic, duodenal, and colonic circadian clocks differ in their persistence under conditions of constant light and in their entrainment by restricted feeding.. Chronobiol Int 2011 Apr;28(3):204-15.
    doi: 10.3109/07420528.2010.548615pubmed: 21452916google scholar: lookup
  32. Benloucif S, Guico MJ, Reid KJ, Wolfe LF, L'hermite-Balériaux M, Zee PC. Stability of melatonin and temperature as circadian phase markers and their relation to sleep times in humans.. J Biol Rhythms 2005 Apr;20(2):178-88.
    doi: 10.1177/0748730404273983pubmed: 15834114google scholar: lookup
  33. Refinetti R, Menaker M. The circadian rhythm of body temperature.. Physiol Behav 1992 Mar;51(3):613-37.
    doi: 10.1016/0031-9384(92)90188-8pubmed: 1523238google scholar: lookup
  34. Murphy BA, Elliott JA, Sessions DR, Vick MM, Kennedy EL, Fitzgerald BP. Rapid phase adjustment of melatonin and core body temperature rhythms following a 6-h advance of the light/dark cycle in the horse.. J Circadian Rhythms 2007 Aug 24;5:5.
    doi: 10.1186/1740-3391-5-5pmc: PMC2020455pubmed: 17718919google scholar: lookup
  35. Boivin DB, James FO, Wu A, Cho-Park PF, Xiong H, Sun ZS. Circadian clock genes oscillate in human peripheral blood mononuclear cells.. Blood 2003 Dec 1;102(12):4143-5.
    doi: 10.1182/blood-2003-03-0779pubmed: 12893774google scholar: lookup
  36. Burgess HJ, Wyatt JK, Park M, Fogg LF. Home Circadian Phase Assessments with Measures of Compliance Yield Accurate Dim Light Melatonin Onsets.. Sleep 2015 Jun 1;38(6):889-97.
    doi: 10.5665/sleep.4734pmc: PMC4434555pubmed: 25409110google scholar: lookup
  37. Akashi M, Soma H, Yamamoto T, Tsugitomi A, Yamashita S, Yamamoto T, Nishida E, Yasuda A, Liao JK, Node K. Noninvasive method for assessing the human circadian clock using hair follicle cells.. Proc Natl Acad Sci U S A 2010 Aug 31;107(35):15643-8.
    doi: 10.1073/pnas.1003878107pmc: PMC2932591pubmed: 20798039google scholar: lookup
  38. Liu LP, Li MH, Zheng YW. Hair Follicles as a Critical Model for Monitoring the Circadian Clock.. Int J Mol Sci 2023 Jan 26;24(3).
    doi: 10.3390/ijms24032407pmc: PMC9916850pubmed: 36768730google scholar: lookup
  39. Yamaguchi S, Mitsui S, Yan L, Yagita K, Miyake S, Okamura H. Role of DBP in the circadian oscillatory mechanism.. Mol Cell Biol 2000 Jul;20(13):4773-81.
    doi: 10.1128/MCB.20.13.4773-4781.2000pmc: PMC85912pubmed: 10848603google scholar: lookup
  40. Yoshitane H, Asano Y, Sagami A, Sakai S, Suzuki Y, Okamura H, Iwasaki W, Ozaki H, Fukada Y. Functional D-box sequences reset the circadian clock and drive mRNA rhythms.. Commun Biol 2019;2:300.
    doi: 10.1038/s42003-019-0522-3pmc: PMC6687812pubmed: 31428688google scholar: lookup
  41. Refinetti R, Lissen GC, Halberg F. Procedures for numerical analysis of circadian rhythms.. Biol Rhythm Res 2007;38(4):275-325.
    doi: 10.1080/09291010600903692pmc: PMC3663600pubmed: 23710111google scholar: lookup
  42. Halberg F, Tong YL, Johnson EA. Circadian System Phase—An Aspect of Temporal Morphology; Procedures and Illustrative Examples. Springer; Berlin/Heidelberg, Germany: 1967. pp. 20–48. (The Cellular Aspects of Biorhythms).
    doi: 10.1007/978-3-642-88394-1_2google scholar: lookup
  43. Bartness TJ, Song CK, Demas GE. SCN efferents to peripheral tissues: implications for biological rhythms.. J Biol Rhythms 2001 Jun;16(3):196-204.
    doi: 10.1177/074873040101600302pubmed: 11407779google scholar: lookup
  44. Brown SA, Zumbrunn G, Fleury-Olela F, Preitner N, Schibler U. Rhythms of mammalian body temperature can sustain peripheral circadian clocks.. Curr Biol 2002 Sep 17;12(18):1574-83.
    doi: 10.1016/S0960-9822(02)01145-4pubmed: 12372249google scholar: lookup
  45. Damiola F, Le Minh N, Preitner N, Kornmann B, Fleury-Olela F, Schibler U. Restricted feeding uncouples circadian oscillators in peripheral tissues from the central pacemaker in the suprachiasmatic nucleus.. Genes Dev 2000 Dec 1;14(23):2950-61.
    doi: 10.1101/gad.183500pmc: PMC317100pubmed: 11114885google scholar: lookup
  46. Ripperger JA, Shearman LP, Reppert SM, Schibler U. CLOCK, an essential pacemaker component, controls expression of the circadian transcription factor DBP.. Genes Dev 2000 Mar 15;14(6):679-89.
    doi: 10.1101/gad.14.6.679pmc: PMC316463pubmed: 10733528google scholar: lookup
  47. Bozek K, Relógio A, Kielbasa SM, Heine M, Dame C, Kramer A, Herzel H. Regulation of clock-controlled genes in mammals.. PLoS One 2009;4(3):e4882.
    doi: 10.1371/journal.pone.0004882pmc: PMC2654074pubmed: 19287494google scholar: lookup
  48. Storch KF, Lipan O, Leykin I, Viswanathan N, Davis FC, Wong WH, Weitz CJ. Extensive and divergent circadian gene expression in liver and heart.. Nature 2002 May 2;417(6884):78-83.
    doi: 10.1038/nature744pubmed: 11967526google scholar: lookup
  49. Welsh DK, Logothetis DE, Meister M, Reppert SM. Individual neurons dissociated from rat suprachiasmatic nucleus express independently phased circadian firing rhythms.. Neuron 1995 Apr;14(4):697-706.
    doi: 10.1016/0896-6273(95)90214-7pubmed: 7718233google scholar: lookup
  50. Yamaguchi S, Isejima H, Matsuo T, Okura R, Yagita K, Kobayashi M, Okamura H. Synchronization of cellular clocks in the suprachiasmatic nucleus.. Science 2003 Nov 21;302(5649):1408-12.
    doi: 10.1126/science.1089287pubmed: 14631044google scholar: lookup
  51. Welsh DK, Yoo SH, Liu AC, Takahashi JS, Kay SA. Bioluminescence imaging of individual fibroblasts reveals persistent, independently phased circadian rhythms of clock gene expression.. Curr Biol 2004 Dec 29;14(24):2289-95.
    doi: 10.1016/j.cub.2004.11.057pmc: PMC3777438pubmed: 15620658google scholar: lookup
  52. Zambon AC, McDearmon EL, Salomonis N, Vranizan KM, Johansen KL, Adey D, Takahashi JS, Schambelan M, Conklin BR. Time- and exercise-dependent gene regulation in human skeletal muscle.. Genome Biol 2003;4(10):R61.
    doi: 10.1186/gb-2003-4-10-r61pmc: PMC328450pubmed: 14519196google scholar: lookup
  53. McCarthy JJ, Andrews JL, McDearmon EL, Campbell KS, Barber BK, Miller BH, Walker JR, Hogenesch JB, Takahashi JS, Esser KA. Identification of the circadian transcriptome in adult mouse skeletal muscle.. Physiol Genomics 2007 Sep 19;31(1):86-95.
    doi: 10.1152/physiolgenomics.00066.2007pmc: PMC6080860pubmed: 17550994google scholar: lookup
  54. Murphy BA, Wagner AL, McGlynn OF, Kharazyan F, Browne JA, Elliott JA. Exercise influences circadian gene expression in equine skeletal muscle.. Vet J 2014 Jul;201(1):39-45.
    doi: 10.1016/j.tvjl.2014.03.028pubmed: 24888677google scholar: lookup
  55. Panda S. Circadian physiology of metabolism.. Science 2016 Nov 25;354(6315):1008-1015.
    doi: 10.1126/science.aah4967pmc: PMC7261592pubmed: 27885007google scholar: lookup
  56. Schibler U, Gotic I, Saini C, Gos P, Curie T, Emmenegger Y, Sinturel F, Gosselin P, Gerber A, Fleury-Olela F, Rando G, Demarque M, Franken P. Clock-Talk: Interactions between Central and Peripheral Circadian Oscillators in Mammals.. Cold Spring Harb Symp Quant Biol 2015;80:223-32.
    doi: 10.1101/sqb.2015.80.027490pubmed: 26683231google scholar: lookup
  57. Kofuji P, Mure LS, Massman LJ, Purrier N, Panda S, Engeland WC. Intrinsically Photosensitive Retinal Ganglion Cells (ipRGCs) Are Necessary for Light Entrainment of Peripheral Clocks.. PLoS One 2016;11(12):e0168651.
    doi: 10.1371/journal.pone.0168651pmc: PMC5161485pubmed: 27992553google scholar: lookup
  58. Fan SM, Chang YT, Chen CL, Wang WH, Pan MK, Chen WP, Huang WY, Xu Z, Huang HE, Chen T, Plikus MV, Chen SK, Lin SJ. External light activates hair follicle stem cells through eyes via an ipRGC-SCN-sympathetic neural pathway.. Proc Natl Acad Sci U S A 2018 Jul 17;115(29):E6880-E6889.
    doi: 10.1073/pnas.1719548115pmc: PMC6055137pubmed: 29959210google scholar: lookup
  59. Hanifin JP, Lockley SW, Cecil K, West K, Jablonski M, Warfield B, James M, Ayers M, Byrne B, Gerner E, Pineda C, Rollag M, Brainard GC. Randomized trial of polychromatic blue-enriched light for circadian phase shifting, melatonin suppression, and alerting responses.. Physiol Behav 2019 Jan 1;198:57-66.
    doi: 10.1016/j.physbeh.2018.10.004pubmed: 30296404google scholar: lookup
  60. Najjar RP, Wolf L, Taillard J, Schlangen LJ, Salam A, Cajochen C, Gronfier C. Chronic artificial blue-enriched white light is an effective countermeasure to delayed circadian phase and neurobehavioral decrements.. PLoS One 2014;9(7):e102827.
    doi: 10.1371/journal.pone.0102827pmc: PMC4114570pubmed: 25072880google scholar: lookup
  61. MacIsaac D, Kanner G, Anderson G. Basic physics of the incandescent lamp (lightbulb). Phys. Teach. 1999;37:520–525.
    doi: 10.1119/1.880392google scholar: lookup
  62. Paus R, Cotsarelis G. The biology of hair follicles.. N Engl J Med 1999 Aug 12;341(7):491-7.
    doi: 10.1056/NEJM199908123410706pubmed: 10441606google scholar: lookup
  63. Lin KK, Kumar V, Geyfman M, Chudova D, Ihler AT, Smyth P, Paus R, Takahashi JS, Andersen B. Circadian clock genes contribute to the regulation of hair follicle cycling.. PLoS Genet 2009 Jul;5(7):e1000573.
    doi: 10.1371/journal.pgen.1000573pmc: PMC2705795pubmed: 19629164google scholar: lookup
  64. O'Brien C, Darcy-Dunne MR, Murphy BA. The effects of extended photoperiod and warmth on hair growth in ponies and horses at different times of year.. PLoS One 2020;15(1):e0227115.
    doi: 10.1371/journal.pone.0227115pmc: PMC6959597pubmed: 31935219google scholar: lookup
  65. Buhr ED, Takahashi JS. Molecular components of the Mammalian circadian clock.. Handb Exp Pharmacol 2013;(217):3-27.
    doi: 10.1007/978-3-642-25950-0_1pmc: PMC3762864pubmed: 23604473google scholar: lookup
  66. Bonmati-Carrion MA, Arguelles-Prieto R, Martinez-Madrid MJ, Reiter R, Hardeland R, Rol MA, Madrid JA. Protecting the melatonin rhythm through circadian healthy light exposure.. Int J Mol Sci 2014 Dec 17;15(12):23448-500.
    doi: 10.3390/ijms151223448pmc: PMC4284776pubmed: 25526564google scholar: lookup
  67. Pauley SM. Lighting for the human circadian clock: recent research indicates that lighting has become a public health issue.. Med Hypotheses 2004;63(4):588-96.
    doi: 10.1016/j.mehy.2004.03.020pubmed: 15325001google scholar: lookup
  68. Murphy BA. Circadian and Circannual Regulation in the Horse: Internal Timing in an Elite Athlete.. J Equine Vet Sci 2019 May;76:14-24.
    doi: 10.1016/j.jevs.2019.02.026pubmed: 31084748google scholar: lookup

Citations

This article has been cited 6 times.
  1. Parmantier S, Kyriazopoulou P, McClendon M, Adams A, Murphy BA. Influence of Extended Photoperiod Using Blue Light Masks on Hypertrichosis, Coat Condition and General Health Parameters in Horses with Pituitary Pars Intermedia Dysfunction. Animals (Basel) 2025 Oct 5;15(19).
    doi: 10.3390/ani15192905pubmed: 41096500google scholar: lookup
  2. Greening L, Harkin E, Kyriazopoulou P, Heppelthwaite Z, Aragona F, Browne JA, Hemmings A, Williams JM, Murphy BA. Influence of lighting on sleep behaviour, circadian rhythm and spontaneous blink rate in stabled riding school horses (Equus caballus). PLoS One 2025;20(6):e0326567.
    doi: 10.1371/journal.pone.0326567pubmed: 40577374google scholar: lookup
  3. Yang M, Li Y, Liang Q, Dong H, Ma Y, Andersson G, Bongcam-Rudloff E, Ahmad HI, Fu X, Han J. Identification of lncRNAs involved in the hair follicle cycle transition of cashmere goats in response to photoperiod change. BMC Genomics 2025 May 15;26(1):487.
    doi: 10.1186/s12864-025-11675-xpubmed: 40375123google scholar: lookup
  4. Harkin EE, Browne JA, Murphy BA. Evaluation of short-term hair follicle storage conditions for maintenance of RNA integrity. PLoS One 2024;19(5):e0294089.
    doi: 10.1371/journal.pone.0294089pubmed: 38820307google scholar: lookup
  5. Farag HI, Murphy BA, Templeman JR, Hanlon C, Joshua J, Koch TG, Niel L, Shoveller AK, Bedecarrats GY, Ellison A, Wilcockson D, Martino TA. One Health: Circadian Medicine Benefits Both Non-human Animals and Humans Alike. J Biol Rhythms 2024 Jun;39(3):237-269.
    doi: 10.1177/07487304241228021pubmed: 38379166google scholar: lookup
  6. Gáspárdy A, Gallagher G, Bartha B, Haaland H, Fekete SG. The Effect of Supplemental Lighting during the Late Gestation Period on Post-Partum Mechanical Properties of Mare and Foal Guard Hair. Vet Sci 2024 Jan 22;11(1).
    doi: 10.3390/vetsci11010049pubmed: 38275931google scholar: lookup
Subscribe to our newsletter
Join 99,850 horse owners like you who receive our email updates on horse health and nutrition.