Abstract
Purpose: :
SPARC is a calcium binding matricellular protein, acidic and rich in cysteine. Hevin shares a high degree of homology with SPARC, displays anti-adhesive properties similar to SPARC. Both are upregulated during embryogenesis and tissue remodeling where it is involved in the regulation of cell adhesion, migration, and proliferation. The present study was undertaken to compare the changes in the intraocular pressure (IOP) and axial components including, axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), and length thickness (LT) in SPARC-null and Hevin null mice to that of wild type (WT) mice.
Methods: :
25 C57Bl6 WT mice, 23 SPARC-null and 28 Hevin null mice of 8 weeks old were selected for the study. All mice were screened with slit lamp and mice with cataract were excluded. TonoLab (Colonial Medical Supply,Franconia, NH) was used to measure IOP from 11am to 3pm for daytime and 9pm to 12pm for night time IOP. Optical low coherence interferometry (OLCI) adapted for short measurement distances by Carl Zeiss (the ‘‘ACMaster’’) was used to measure axial components between 11am and 4pm.
Results: :
Hevin-null mice showed higher IOP, SPARC-null mice showed lower IOP compared to WT mice during the day as well as night time. Hevin-null and SPARC-null mice showed significantly increased AL and CCT compared to WT mice. There was no significant difference between Hevin-null and SPARC -null mice. SPARC-null showed significantly increased LT and significantly decreased ACD compared to WT mice and Hevin-null mice. There was no significant difference in LT and ACD between WT and Hevin-null mice.
Conclusions: :
Hevin null mice showed a significant higher IOP, SPARC-null a significant lower IOP values throughout the day and night. Increased LT of SPARC-null mice was observed even before the development of cataract. Increased CCT of Hevin-null mice could be one of the factors resulting in increased IOP. Decreased ACD of SPARC-null mice can be one of the factors resulting in decreased IOP in SPARC-null mice.
Keywords: intraocular pressure • anterior chamber • cornea: stroma and keratocytes