Evaluation of new robust silk fibroin hydrogels for posterior scleral reinforcement in rabbits

Yule Xu; Qiaolin Chen; Zhengzhong Shao; Jiahong Wei; Xuyou Zhu; Ao Rong; Xin Chen; Yusu Ni; Yi Jiang

doi:10.3389/fbioe.2023.1211688

Evaluation of new robust silk fibroin hydrogels for posterior scleral reinforcement in rabbits

Front Bioeng Biotechnol. 2023 Jun 14:11:1211688. doi: 10.3389/fbioe.2023.1211688. eCollection 2023.

Authors

Yule Xu¹, Qiaolin Chen², Zhengzhong Shao², Jiahong Wei¹, Xuyou Zhu³, Ao Rong^{1

4}, Xin Chen², Yusu Ni^{5

6

7}, Yi Jiang⁴

Affiliations

¹ Department of Ophthalmology, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China.
² State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Laborarory of Advanced Materials, Fudan University, Shanghai, China.
³ Department of Pathology, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China.
⁴ Department of Ophthalmology, Shanghai Xin Shi Jie Eye Hospital, Shanghai, China.
⁵ Otology and Skull Base Surgery Department, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai, China.
⁶ Key Laboratory of Hearing Medicine of National Health and Family Planning Commission, Shanghai, China.
⁷ Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.

Abstract

Background: Currently, there is no ideal material available for posterior scleral reinforcement (PSR) to prevent the progression of high myopia. In this study, we investigated robust regenerated silk fibroin (RSF) hydrogels as potential grafts for PSR in animal experiments to evaluate their safety and biological reactions. Methods: PSR surgery was performed on the right eye of twenty-eight adult New Zealand white rabbits, with the left eye serving as a self-control. Ten rabbits were observed for 3 months, while 18 rabbits were observed for 6 months. The rabbits were evaluated using intraocular pressure (IOP), anterior segment and fundus photography, A- and B-ultrasound, optical coherence tomography (OCT), histology, and biomechanical tests. Results: No complications such as significant IOP fluctuation, anterior chamber inflammation, vitreous opacity, retinal lesion, infection, or material exposure were observed. Furthermore, no evidence of pathological changes in the optic nerve and retina, or structural abnormalities on OCT, were found. The RSF grafts were appropriately located at the posterior sclera and enclosed in fibrous capsules. The scleral thickness and collagen fiber content of the treated eyes increased after surgery. The ultimate stress of the reinforced sclera increased by 30.7%, and the elastic modulus increased by 33.0% compared to those of the control eyes at 6 months after surgery. Conclusion: Robust RSF hydrogels exhibited good biocompatibility and promoted the formation of fibrous capsules at the posterior sclera in vivo. The biomechanical properties of the reinforced sclera were strengthened. These findings suggest that RSF hydrogel is a potential material for PSR.

Keywords: biocompatibility; biomaterial; myopia; posterior scleral reinforcement; silk fibroin.

Grants and funding

This work was funded by the Science and Technology Committee of Changning District, Shanghai (CNKW 2020Y59), the Clinical Research Plan of SHDC (SHDC2020CR1043B), and the Clinical Research Program of Shanghai Tongji Hospital [ITJ(QN)1904].