Wound healing of corneal epithelium in mice affected by reversed circadian rhythms

Authors: He Jingxin,  Lin Yan,  Xu Pengyang,  Xue Yunxia,  Li Zhijie

DOI: 10.3760/cma.j.issn.2095-0160.2019.07.004
Published 2019-07-10
Cite as Chin J Exp Ophthalmol, 2019,37(7): 514-520.

Abstract

Objective

To observe the effect of reversed circadian rhythms on wound healing of mouse corneal epithelium.

Methods

Ninety male C57BL/6 mice were divided into LD group (12 hours light/12 hours dark) and DL group (12 hours dark/12 hours light) by random number table, and then were placed in circadian rhythm box for 12 days.The circular area was scarped and marked as 2 mm diameter area in the center of the mouse’s cornea with a golf-like knife.The dynamics of epithelial healing in the wound area were observed under microscope by fluorescein staining and hematoxylin-eosin staining.Besides, being marked antibodies of anti-Ly6G-FITC, anti-γδT-PE and DAPI, dynamic changes of the dividing cells, neutrophils and γδT cells were also investigated for every 6 hours until 42 hours.All mice were treated in accordance with the Association for Research in Vision and Ophthalmology’s Statement for the Use of Animals in Ophthalmology and Vision Research and the guidelines of the Animal Experimental Committee at Jinan University (JN-A-2002-01).

Results

In LD group, percentage of corneal epithelial defective area were (100.000±0.000)%, (37.677±5.243)%, (14.959±1.739)% and (0.000±0.000)% after wounding 0 hour, 6, 12, 18 and 24 hours.In DL group, percentage of the corneal epithelial defective area were (100.000±0.000)%, (10.967±1.065%)%, (1.985±0.106)% and (0.000±0.000)% after wounding 0 hour, 6, 12, 18 and 24 hours.The healing rate in DL group was higher than that in LD group, with a significant difference between them (P<0.05). As with the uninjured corneal, thickness of corneal epithelium was (33.983±1.074)μm in DL group and (33.993±0.904)μm LD group, with no statistically significant difference between them (P>0.05). After 24 hours, thickness of corneal epithelium in DL group was (19.473±0.856)μm, and was more than that in LD group [(17.485±0.718)μm], with a significant difference between them (P<0.05). Paraffin section of wounded corneal epithelium after 24 hours by hematoxylin and eosin staining showed that corneal epithelium cells arranged loosely and disorderly and were in irregular shape in both groups.The epithelium were mainly basal cells in LD group, while epithelium included basal cell and a few pinacocytes in DL group.After corneal epithelium wounded, the number of cell division, neutrophils and corneal limbus γδT cells in two groups were statistically significant difference, respectively(P<0.05).

Conclusions

Reversed circadian rhythms can significantly regulate the wound healing of corneal epithelium.

Key words:

Cornea; Reversed circadian rhythms; Wound healing; Inflammation

Contributor Information

He Jingxin
Department of Ophthalmology, the First Affiliated Hospital of Jinan University, Guangzhou 510632, China
Lin Yan
Key Laboratory for Regenerative Medicine, Jinan University, Guangzhou 510632, China
Xu Pengyang
Department of Pathophysiolgy, Medical College, Jinan University, Guangzhou 510632, China
Xue Yunxia
Institute of Ophthalmology, Medical College of Jinan University, Guangzhou 510632, China
Li Zhijie
Institute of Ophthalmology, Medical College of Jinan University, Guangzhou 510632, China
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Updated: September 25, 2019 — 7:50 am