Photochemical activation increases the porcine corneal stiffness and resistance to collagenase digestion.
In this study, we explore the effect of photochemical activation induced corneal cross-linking, utilizing Rose Bengal (RB) and 532 nm green light irradiation (RB-PCL), on porcine corneal biomechanical rigidity and the biochemical resistance against collagenase digestion. A protocol with a wavelength of 532 nm and illumination intensity of 0.4W/cm(2) for 250 s to deliver a dose of 100 J/cm(2) was chosen. Using confocal microscopy, we demonstrated that the diffusion depth of RB into porcine cornea was approximately 150 μm and mostly localized in anterior stroma 25 min followed by RB application. After photochemical cross-linking, an increase in tensile strength (by average 200%) and Young's modulus (by average 200%) in porcine corneas was observed. The corneal buttons treated by RB-PCL showed doubling of collagenase digestion time from 10.8 ± 3.1 days in the blank group to 19.7 ± 6.2 days in the RB-PCL group, indicating increased resistance to enzymatic digestion. In conclusion, Collagen cross-linking by RB-PCL increased both the biomechanical stiffness and the biochemical resistance against collagenase digestion in porcine corneas, therefore to allow stabilizing and solidifier the cornea. The advantages and disadvantages of RB-PCL versus UVA/riboflavin cross-linking technique (UV-CXL) are fully explored. Due to the nature of minimal penetration of RB into corneal stroma, the RB-PCL method could potentially be used in patients with corneal thickness less than 400 μm where UV-CXL is limited.
Department of Ophthalmology, The 85th Hospital of PLA, Shanghai 200052, China.
Ti
T
Wang
Department of Burns and Plastic Surgery, No. 3 People's Hospital, and Institute of Traumatic Medicine, School of Medicine, Shanghai Jiao Tong University, Shanghai 201900, China.
Yinbo
Y
Peng
Department of Ophthalmology, Huadong Hospital Affiliated to Fudan University, Shanghai 200040, China.
Nianci
N
Shen
RA Consulting, 104 Aspen Court, Chalfont, PA 18914, USA.
Yan
Y
Yu
Department of Burns and Plastic Surgery, No. 3 People's Hospital, and Institute of Traumatic Medicine, School of Medicine, Shanghai Jiao Tong University, Shanghai 201900, China; Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
Min
M
Yao
Department of Ophthalmology, Huadong Hospital Affiliated to Fudan University, Shanghai 200040, China. Electronic address: jingyinz@gmail.com.
Jingyin
J
Zhu
D000818:Animals; D001831:Body Temperature; D003094:Collagen / Q000378:metabolism; D017364:Collagenases / Q000494:pharmacology*; D003315:Cornea / Q000187:drug effects* / Q000378:metabolism; D003432:Cross-Linking Reagents; D004548:Elasticity / Q000187:drug effects; D005456:Fluorescent Dyes / Q000494:pharmacology*; D053844:Lasers, Solid-State; D008027:Light; D018613:Microscopy, Confocal; D055668:Photochemical Processes; D017319:Photosensitizing Agents / Q000494:pharmacology*; D012395:Rose Bengal / Q000494:pharmacology*; D013552:Swine; D013718:Tensile Strength / Q000187:drug effects*
D003432:Cross-Linking Reagents; D005456:Fluorescent Dyes; D017319:Photosensitizing Agents; D012395:Rose Bengal; D003094:Collagen; D017364:Collagenases
Rose Bengal; collagenase; corneal cross-linking; photochemical activation; tensile strength