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Fatima Pedrosa Domellof, Maria Angels Rodriguez Garcia, Andre Vicente, Karin Sandgren Hochhard; Sarcomere remodelling and gene expression profile changes following strabismus surgery. Invest. Ophthalmol. Vis. Sci. 2018;59(9):1146.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate the extent and time axis of sarcomere remodeling and of gene expression profile changes following resection surgery in an animal model of strabismus surgery.
The right superior rectus (SR) of 16 adult New Zealand white rabbits was resected 4 mm and reattached to the sclera, with ethical permission and following the animal care directives. The superior rectus muscle of 4 rabbits was collected 1, 2, 4 and 6 weeks after surgery. The SR of 4 control rabbits was also collected. The muscles were divided into two pieces longitudinally and one half was directly frozen for RNA extraction and the other half was stretched, fixed in 2% paraformaldehyde and frozen after sucrose cryoprotection. Serial longitudinal sections were processed for immunohistochemistry with antibodies against desmin. For each muscle section, the area comprising exclusively longitudinally sectioned myofibers was evaluated and the number of dividing sarcomeres present within that area was determined. RNA sequencing was performed with Illumina HiSeq 2500.
One week after surgery, the number of sarcomere divisions was 86.5/mm2 (range 30.9-152.7), after two weeks 72.0/ mm2 (42.5-95.9), after 4 weeks 95.7/ mm2 (37.4-161.3). After 6 weeks the number of sarcomere divisions (26.8/ mm2, 9.2-60.7) was similar to that of the control samples (26.0/ mm2, 6.0-66.9).RNA sequencing revealed up to 198 differentially expressed genes and further bioinformatics analysis is ongoing. Preliminary data indicate that the most significantly altered biological processes are those involved in extracellular matrix organization and inflammation, along with regulation of response and production of growth factors involved in muscle repair and regeneration.
Signs of sarcomerogenesis were present during the first 4 weeks after resection of the superior rectus, suggesting that sarcomerogenesis plays a role in surgical failure due to recovery of muscle length. We suggest that medical approaches to limit this mechanism may be a desirable complementary therapy to strabismus surgery in the future.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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