Sonic hedgehog expression and its role in form-deprivation myopia in mice.
OBJECTIVE
To investigate whether sonic hedgehog (Shh) plays a role in postnatal eye development and the development of experimentally induced myopia.


METHODS
Expression of Shh, Patched-1 (Ptc-1), and Gli3 was evaluated in the eyes of 13- to 14-day-old C57B/L6 mice with form-deprivation myopia (FDM) (n = 100) and controls (n = 100) using real-time PCR and Western blot analysis. In a second experiment, 336 mice were divided into two groups: the first wore a unilateral translucent diffuser to induce myopia and the second served as a control. Both groups received four intravitreal injections of either Shh-N (Sonic hedgehog amino-terminal peptide) or cyclopamine (a specific inhibitor of the Shh pathway) every other day. Retinoscopic refraction and axial length measurements were performed on the 11th day of form deprivation. Sections of the eyes were observed using a light microscope.


RESULTS
Inducing myopia caused a significant increase in expression of Shh mRNA (7 days: t = 6.09, p = 0.004; 14 days: t = 3.48, p = 0.025) and protein (7 days: t = 4.06, p = 0.015; 14 days: t = 4.25, p = 0.013). Expression of both Gli3 mRNA (t = 7.61, p = 0.002) and protein (t = 2.89, p = 0.045) increased after 7 days of occlusion. Administration of Shh-N stimulated the development of myopia and axial growth in both occluded (refraction: F = 7.49, p = 0.001; axial length: F = 9.89, p < 0.001) and non-occluded eyes (refraction: F = 14.20, p < 0.001; axial length: F = 20.37, p < 0.001). Cyclopamine reduced myopic refractive error and axial elongation in occluded eyes (refraction: F = 27.91, p < 0.001; axial length: F = 15.18, p < 0.001). It also influenced non-occluded eyes, reducing axial growth and shifting the refraction toward hyperopia (refraction: F = 14.81, p < 0.001; axial length: F = 3.99, p = 0.024). No difference in retinal thickness was found between experimental and control eyes.


CONCLUSIONS
The Shh signaling pathway may influence both form-deprivation myopia and the postnatal growth of eyes with normal visual input.
Qian
Yi-Shan
YS
Department of Ophthalmology, Eye, Ear, Nose, Throat Hospital, Fudan University, Shanghai Medical College, Shanghai.
Chu
Ren-Yuan
RY
Hu
Min
M
Hoffman
Matthew R
MR
D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D004195:Disease Models, Animal; D005123:Eye / Q000254:growth & development; D005786:Gene Expression Regulation / Q000502:physiology*; D053823:Hedgehog Proteins / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000235:genetics*; D051741:Kruppel-Like Transcription Factors / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D009216:Myopia / Q000235:genetics* / Q000503:physiopathology / Q000517:prevention & control; D009419:Nerve Tissue Proteins / Q000235:genetics; D000072079:Patched Receptors; D000072081:Patched-1 Receptor; D012333:RNA, Messenger / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics; D042262:Retinoscopy; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012683:Sensory Deprivation; D015398:Signal Transduction / Q000502:physiology; D014704:Veratrum Alkaloids / Q000494:pharmacology; D000074290:Zinc Finger Protein Gli3
C465571:Gli3 protein, mouse; D053823:Hedgehog Proteins; D051741:Kruppel-Like Transcription Factors; D009419:Nerve Tissue Proteins; D000072079:Patched Receptors; D000072081:Patched-1 Receptor; C000606240:Ptch1 protein, mouse; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; C465570:Shh protein, mouse; D014704:Veratrum Alkaloids; D000074290:Zinc Finger Protein Gli3; C000541:cyclopamine