difference between ischemia and oxygen-glucose deprived medium
Ischemia leads to tissular hypoxia and glycopenia due to an insufficient blood flow (e.g. due to atherosclerosis or thromboembolic diseases). Ischemia always result in hypoxia.

Hypoxia can occur without ischemia (e.g. due to anemia).

Tissular glycopenia can occur without ischemia (e.g. due to hypoglicemia).

Ischemia is a shortage in blood supply. Depriving cells form oxygen and glucose isn't the same as cutting their blood supply.