Figure 3. Pharmacological blockers of PKA and Erk pathways abolished α-MSH’s amelioration on corneal dysfunctions in the dry eye rats.
α-MSH, at the optimal dose of 10−4 mg/ml, significantly improved the values of Schirmer’s test (A), tear breakup time (B), and corneal fluorescein staining (C,D) in the dry eye rats. Addition of H89 and PD98059, the pharmacological blockers to PKA and Erk pathways, respectively, abolished α-MSH’s amelioration on the corneal dysfunctions in the dry eye rats (A–D). The representative pictures of corneal fluorescein staining were shown (C). n = 16–32 per group. **p < 0.01, ***p < 0.001. D = dry eye, NaCl = saline, PD = PD98059.