Effect of Cryopreserved Amniotic Membrane on the Mechanical Properties of Skeletal Muscle after Strabismus Surgery in Rabbits

ABSTRACT

Purpose: To study the functional recovery of the superior rectus muscle (SRM) after its partial resection in a rabbit model with and without cryopreserved amniotic membrane (AM).

Material and methods: Resection of the right and left SRMs of 30 rabbits was performed. On the left eyes, a single sheet of equine cryopreserved AM was placed covering the muscle edge sutured. Active and passive mechanical properties of muscles operated with and without AM were monitored over time at 30 (n = 10), 60 (n = 10), and 90 (n = 10) days after surgery. Muscle samples were extracted and electrically stimulated to register the force exerted by the samples, characterizing its active behavior. They were, then, subjected to stretching test to obtain its resistance to deformation, known as passive behavior. Moreover, right and left eyes of a control group (n = 5) were equally subjected to active and passive tests to characterize the physiological behavior of SRM muscles.

Results: On active function examination, statistically significant differences were documented between the following: control vs AM and no AM at 30 days (p = 0.002 and p = 0.04, respectively). All other comparisons were insignificant (p > 0.05). On passive function analysis, significant differences were only found between control vs. no AM at 30 days (p = 0.004) and between AM vs. no AM at 30 days (p = 0.002). Indeed, muscle operated without AM did not recover a normal passive function until 60 days after surgery.

Conclusion: Cryopreserved AM is effective in accelerating recovery of SRM passive function in rabbits. Nevertheless, AM produced no significant effect on recovery of SRM active function.


KEYWORDS:

• Rabbit
• amniotic membrane
• strabismus
• extraocular muscle
• mechanical behavior

Acknowledgments

The authors gratefully acknowledge Carlos III Health Institute (ISCIII) through the CIBER initiative and the ICTS NANBIOSIS, specifically by the Tissue & Scaffold Characterization Unit (U13) of CIBER-BBN. The authors also thank the Government of Aragón and the Spanish Ministry of Education, Culture and Sports for the financial supports to M. Sierra and A. Ortillés, respectively, and the use of Service General Research Support (SAI), University of Zaragoza. The authors are grateful to AJL Ophthalmic S.A. (Victoria-Gasteiz, Spain) for providing sutures (Sinusorb®).

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Funding

This work was supported by the Spanish Ministry of Economy and Competitiveness (Project DPI2014-54981-R), second project from Spanish Ministry of Economy and Competitiveness (DPI2017-84047-R), Department of Industry and Innovation (Government of Aragón), and European Social Fund 2014-2020 (FSE-DGA T88).

Additional information

Funding

This work was supported by the Spanish Ministry of Economy and Competitiveness (Project DPI2014-54981-R), second project from Spanish Ministry of Economy and Competitiveness (DPI2017-84047-R), Department of Industry and Innovation (Government of Aragón), and European Social Fund 2014-2020 (FSE-DGA T88).