Metformin prevents leukocyte infiltration and microglia activation in the retinas of NMDA-injected eyes. The numbers of CD45-positive cells and Iba1-positive cells were counted one day after intravitreal injection of NMDA. (A): Saline + vehicle (a,a’,a”); saline + metformin (b,b’,b”); NMDA + vehicle (c,c’,c”); NMDA + metformin (d,d’,d”). The doses of NMDA and metformin were 200 and 20 nmol/eye, respectively. Arrowheads indicate CD45- and Iba1-double-positive cells. Blue nuclei: 4′,6-diamidino-2-phenylindole (DAPI). Scale bar, 50 µm. (B): Bar graphs showing the number of CD45-positive cells and Iba1-positive cells present in the ganglion cell layer (GCL) and inner plexiform layer (IPL) of each retina. n = 5–6. ** p < 0.01; ns: no significance; Kruskal–Wallis test.