*2.2.4 Ceruloplasmin/hephaestin double knockout (DKO) mice*

Iron can be a source of oxidative stress and its transport is mediated by ceruloplasmin, transferrin, and hephaestin [15, 17]. Humans lacking ceruloplasmin can develop AMD in middle age. Ceruloplasmin/hephaestin DKO mice by 6–9 months of age developed focal RPE hypertrophy, increased lipofuscin, photoreceptor atrophy, and subretinal deposits and neovascularization [15, 17]. Retinal changes peak by about 12 months of age, showing signs of oxidative damage and complement deposition [15]. Studying the retinal changes in older mice of this DKO strain is limited, however, due to a movement-related premature death caused by the DKO of ceruloplasmin/hephaestin [17]. Hadziahmetovic *et al.* showed that oral iron chelator deferiprone given to ceruloplasmin/hephaestin DKO mice decreases iron levels and can mitigate retinal degeneration [30]. These findings suggest that iron may play a role in AMD pathology.

### *2.2.5 Cigarette smoke/hydroquinone exposure in mice*

Cigarette smoke contains many toxins and oxidants, the most abundant of which is hydroquinone (HQ ). C57BL/6 J mice at 16 months of age were fed a highfat diet (HFD) for 4.5 months causing the mice to develop sub-RPE deposits when exposed to oxidative stress. The mice were then divided into two groups to examine the additive effects of cigarette smoke and HQ on a HFD. The mice were exposed to a combination of HFD with blue light (positive control), cigarette smoke, or oral HQ. Espinosa-Heidmann *et al.* found that mice fed a HFD yet had no oxidative stress exposure showed normal retinal morphology, while mice exposed to oxidative stress through blue light, cigarette smoke, or oral HQ demonstrated retinal changes similar to early AMD, such as sub-RPE deposits and BrM thickening [31]. Furthermore, mice treated with HQ in their drinking water were found to have more proangiogenic VEGF compared to anti-angiogenic PEDF. The imbalance of angiogenic factors from HQ may contribute to CNV [17]. These findings may partly explain why cigarette smoking is an influential risk factor in AMD.

### **2.3 Rodents models of inflammation**

Inflammation is associated with AMD onset and progression with complement being a major component. Inflammatory components found in drusen further support inflammation taking a role in AMD pathogenesis [15]. Below are a few example models of inflammation and the complement pathway.
