Figure 6. Bim deficiency alters glaucomatous insult in DBA/2J mice.

To test importance of BIM in glaucomatous RGC death, a null allele of Bim was backcrossed into DBA/2J for at least 10 generations (D2.Bim^-). The optic nerve head is the likely location of an important glaucomatous insult. (A) Since the optic nerve head was abnormal in B6.Bim^-/- eyes we examined optic nerve head morphology in D2.Bim^-/- mice. In 5 out of 5 D2.Bim^-/- optic nerve heads examined there were clear abnormalities similar to those seen in B6.Bim^-/-. Most notably there were abnormal retinal optic nerve head borders (asterisk) and the gross arrangement of the glial cells in the area of the glial lamina (arrow) was poorly organized. Thus, it is possible that in D2.Bim^-/- mice the changes in optic nerve head morphology alter the susceptibility of D2.Bim^-/-to ocular hypertension induced neuronal injury. (B) The IOP profile of D2.Bim^+/+ mice was similar to previous reports²⁹. At 9, 10.5 and 12 months of age IOP was significantly elevated compared to younger mice (P<0.001 for each age). The IOP in 4 month old D2.Bim^-/- mice was not different to young D2.Bim^+/+ mice (P = 0.68). There was also no significant increase in IOP in D2.Bim^-/- mice at 9 or 10.5 months of age. IOP was significantly increased in D2.Bim^-/- at 12 months of age (P<0.001). Thus, Bim deficiency appears to delay, but not prevent IOP elevation in DBA/2J mice. N≥24 for all ages and genotypes. Scale bar, 50 μm.