Abstract
Purpose: :
To determine whether absence of C1q affects glaucomatous RGC loss
Methods: :
C1q knockout (KO) congenic DBA/2 mice were generated by breeding into the D2 strain for 10 generations and were then allowed to age. IOP of a subgroup of male KOs and heterozygote littermates were recorded from the 6th to the 12th month of age. RGCs of 7 KOs and 5 heterozygotes males were retrogradely labeled at 12 months and counted after imaging flat mounts. Total retinal area was measured.
Results: :
Mean, peak and cumulative IOP exposure were similar in heterozygote and KO eyes (p>0.78 t-test). Mean RGC counts were ~29.6K for heterozygotes and ~40.3K for KOs (p>0.28 t-test, power 0.18). RGC loss in the least affected eye of each animal was more severe (RGC counts of less than 35K) in heterozygotes than KOs (p<0.03, Fisher’s exact). Total retinal area was significantly larger in heterozygotes compared to KOs (p<0.04, t-test). RGC counts correlated weakly (inversely) with mean IOP (R2=0.41) while total retinal area correlated very weakly (also inversely) with maximum IOP (R2=0.24).
Conclusions: :
C1q KOs in the DBA/2 background have slightly decreased glaucomatous RGC loss and decreased retinal area compared to heterozygote littermates. IOP differences could not account for these differences.
Keywords: ganglion cells • inflammation • retina: proximal (bipolar, amacrine, and ganglion cells)