Tear secretion from the main lacrimal gland (LG) is mainly regulated by parasympathetic nerves. We performed several innervation studies to investigate lacrimation.
In male rabbits, we performed a retrograde dye-tracing study of LG innervation, evaluated preganglionic parasympathetic denervation, and administered glial cell–derived neurotrophic factor (GDNF) in the surgical area after parasympathetic denervation.
Accumulation of fluorescent dye was observed in the pterygopalatine ganglion cells on the same side as the dye injection into the main LG. Fewer stained cells were observed in the cervical and trigeminal ganglia. After parasympathetic denervation surgery, tear secretion was decreased, and fluorescein and rose bengal staining scores were increased at day 1 after surgery and remained increased for 3 months on the denervated side only. Most of the effects in rabbits with parasympathetic denervation were not recovered by administration of GDNF.
The main LG is primarily innervated by parasympathetic nerves to stimulate tear secretion. After preganglionic parasympathetic denervation, lacrimation was decreased, resulting in dry eyes, and this was maintained for at least 3 months. Administration of GDNF only minimally altered the effects of denervation.
*Department of Ophthalmology, Juntendo University School of Medicine, Shizuoka, Japan; and
†Department of Ophthalmology, Tokyo Women's Medical University Medical Center East, Tokyo, Japan.
Correspondence: Hiroshi Toshida, MD, PhD, Department of Ophthalmology, Juntendo University School of Medicine, 1129, Nagaoka, Izunokuni, Shizuoka 410-2295, Japan (e-mail: email@example.com).
H. Toshida has received research grants from the Japan Society for the Promotion of Science (JSPS) Kakenhi Grant-in-Aid for Scientific Research (C) (grant number 15K 10904) and the Ministry of Education, Culture, Sports, Science and Technology (MEXT)-Supported Program from the Strategic Research Foundation at Private Universities, 2015 to 2019. C. Suto has received a JSPS Kakenhi Grant-in-Aid for Scientific Research (C) (grant number 15K 10904).
The authors have no conflicts of interest to disclose.
Received June 29, 2018
Accepted July 04, 2018