Figure 4. Comparison of TRP and Piezo channel mRNA levels in the optic nerve head between C57BL/6 (n=6, gray bars) and DBA/2J (n=6, black bars) strains. Normal DBA/2J mice with no or early glaucoma were used in this experiment. DBA/2J Gpnmb+ (n=3, white bars) mice were used as another control for DBA/2J. Expression of eight transient receptor potential (TRP) (A–D) and two Piezo (E) genes that were detected in astrocytes dissociated from the optic nerve head were determined with quantitative real-time PCR. Data represent fold differences relative to the same genes of C57BL/6. Significant expression differences for each gene between the three groups were assessed using Kruskal–Wallis ANOVA followed by a Mann–Whitney test. *p<0.05. Error bar, mean ± SEM.