To further test the effects of SP treatment, we evaluated mRNA expression of Th1-type and proinflammatory cytokines/chemokines after
P. aeruginosa infection. Normal, uninfected corneas and corneas at 1, 3, 5, and 7 days p.i. were analyzed by real-time RT-PCR; mRNA expression levels are shown in
Figure 2A 2B 2C 2D 2E . IFN-γ
(Fig. 2A)was not detected in the normal, uninfected cornea but was significantly increased in SP- compared with PBS-treated mice at 1 (
P = 0.0003), 5 (
P = 0.04), and 7 days p.i. (
P = 0.02). No difference was detected between the two groups at 3 days p.i. (
P = 0.30). A significant increase in IL-18 mRNA expression
(Fig. 2B)was detected in SP-treated mice at 1, 3, 5, and 7 days p.i. (
P < 0.0001,
P = 0.004,
P = 0.005, and
P = 0.05, respectively) when compared with PBS-treated controls. No signal for IL-18 was detected in normal, uninfected samples. TNF-α
(Fig. 2C)was constitutively expressed in normal, uninfected BALB/c cornea and was significantly elevated in SP-treated compared with PBS-treated controls at 3, 5, and 7 days p.i. (
P = 0.005,
P = 0.001, and
P = 0.04, respectively). TNF-α mRNA corneal expression levels were similar in SP- and PBS-treated mice at 1 day p.i. (
P = 0.45). mRNA expression of IL-6
(Fig. 2D)was not detected in the normal, uninfected cornea and was significantly higher in SP-treated mice only at 5 and 7 days p.i. (
P = 0.003 and
P = 0.05, respectively). No significant differences were detected between the two groups at days 1 or 3 p.i. (
P = 0.1 and
P = 0.07, respectively). MIP-2 mRNA expression
(Fig. 2E)was not detected in the normal, uninfected BALB/c cornea. Expression of MIP-2 mRNA was significantly upregulated by SP treatment at 3, 5, and 7 days p.i. (
P = 0.01,
P = 0.003, and
P = 0.03, respectively). MIP-2 levels were similar between SP- and PBS-treated mice at 1 day p.i. (
P = 0.95)