Abstract
Abstract: :
Purpose: Glaucoma is a major cause of blindness throughout the world. The DBA/2J mouse model of hereditary glaucoma has been previously described. The model demonstrates chronic progressive increases in intraocular pressure (IOP) and optic nerve damage with age. In this study, we investigated whether retinal cell injury occurs in DBA/2J mice coincident with an increase in IOP measured with a Tono-pen handheld tonometer. Methods: DBA/2J (n=8)mice, ages 2 months to 12 months, were used for this study. C57BL/6J (n=9) age-matched controls were used for comparison. Animals were anesthetized with ketamine/xylazine and IOP was measured using a Tono-pen tonometer. Paraformaldeyde-fixed, frozen retinal sections were used for histochemical detection of DNA fragmentation by TUNEL assay. Results: IOP of DBA/2J compared with C57BL/6 mice at 2, 4, and 8 months of age showed no differences. By 10 months of age, the IOP of the DBA/2J mice was increased (32 mm Hg) compared to the C57BL/6J mice (7 mm Hg). DBA/2J mice at 12 months of age had an IOP of 45 mmHg . There was no retinal TUNEL-positive staining evident in either the DBA/2J or C57BL/6J at the indicated ages studied. Conclusion: Consistent IOP measurements from the mouse eye are possible with the Tono-pen tonometer. A general trend of increased pressures was observed with increasing age. The lack of TUNEL staining suggests a mechanism of retinal cell injury other than apoptosis in the DBA/2J retina between developmental ages 2-12 months.
Keywords: 444 intraocular pressure • 323 apoptosis/cell death • 474 microscopy: light/fluorescence/immunohistochemistry