Figure 5. Effect of diabetes on expression of the glutamate transporters SLC1A3, VGLUT1, VGLUT2, and VGLUT3. qRT-PCR analysis was performed
on cDNA isolated from control and STZ-induced diabetic rat retinas after 4 and 12 weeks. Expression of each gene was normalized
to acidic ribosomal phosphoprotein (P0) for each rat (A), and then scaled to the 4-week control rats for each gene (B; mean ± SEM). The SLC1A3 mRNA levels in the 12-week diabetic rats were significantly lower than those of the 4-week control
rats and 4-week diabetic rats (###, p<0.005; ####, p<0.001). The 12-week diabetic rats also had lower SLC1A3 mRNA levels than
the 12-week control rats, but the difference was not quite significant (p=0.0522). The 12-week diabetic rats had significantly
lower VGLUT1 mRNA levels than the age-matched control rats (***, p<0.005). VGLUT2 mRNA was significantly higher in the 4-week
diabetic rats compared to the 12-week diabetic rats (#, p<0.05). VGLUT2 mRNA levels in the 4-week diabetic rats increased
1.25 fold over the 4-week control rats, but the difference was not quite significant (p=0.0503).