Time-course of changes to nitric oxide signaling pathways in form-deprivation myopia in guinea pigs.
The aim of this study was to investigate the time-course change of nitric oxide synthase (NOS) activity and cyclic GMP (cGMP) concentration in the posterior retina, choroid and sclera after differing periods of form-deprivation in guinea pigs. Three groups of guinea pigs were subjected to monocular FD for 7, 14 or 21 days. NOS activity and cGMP concentrations in ocular tissues of FD eyes and control eyes were analyzed by radioimmunoassay. The presence of NOS isoforms was detected by immunohistochemistry. Guinea pigs presented with considerable myopia after 14 days of FD. Retinal NOS activity in the FD group was lower than in the control group after 7 days of FD and was higher than in the control group after 14 and 21 days of FD. The choroidal and scleral NOS activities in the FD groups were higher than in the control groups after 21 days. The cGMP concentrations in the FD groups were higher than in the control groups at 21 days of the retinal, choroidal, and scleral tissues. Furthermore, the retinal cGMP concentration in the FD group was also significantly elevated at 14 days relative to the control group. We detected expression of three NOS isoforms in guinea pig ocular tissues. Our main observations were a change in NOS activity and an up-regulation in cGMP concentrations in posterior ocular tissues during the development of myopia. The function of elevated NOS activity may be mediated by cGMP.
Wu
Jie
J
State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlie Road, Guangzhou, GuangDong, China.
Liu
Qiong
Q
Yang
Xiao
X
Yang
Hui
H
Wang
Xin-Mei
XM
Zeng
Jun-Wen
JW
D000818:Animals; D002829:Choroid / Q000166:cytology / Q000201:enzymology; D006152:Cyclic GMP / Q000378:metabolism*; D004195:Disease Models, Animal; D005556:Form Perception / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology; D006168:Guinea Pigs; D007527:Isoenzymes / Q000378:metabolism; D009216:Myopia / Q000201:enzymology*; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D011897:Random Allocation; D012160:Retina / Q000166:cytology / Q000201:enzymology*; D012590:Sclera / Q000166:cytology / Q000201:enzymology; D015290:Second Messenger Systems / Q000502:physiology; D012683:Sensory Deprivation / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D013997:Time Factors
D007527:Isoenzymes; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D006152:Cyclic GMP