| Objectives: To evaluate the effects of PEDF eyedrops on the corneal allograft rejection by topical installition on the rat model of penetrating keratoplasty, and to investigate its possible mechanism and its clinical signification. Methods: Penetrating keratoplasty(PKP) was proformed orthotopically from Wistar rats to SD rat' recipients. 72 SD rats were randomly assigned to two groups-experimental group and control group after PKP. The experimental group was treated with PEDF eyedrops, the Control group was treated with escipient eyedrops. All animals' rejection index which included the corneal opacity, edema and CNV, the rejection time and survival time were recorded and compared by the biomicroscope examination. The area of CNV was caculated quantitatively. 6 animals in both groups were killed respectively at the 1st week, 2nd week, 3rd week, 1st month, 2nd month and 3rd month postoperatively. CNV and inflammation were evaluated with HE staining. Corneal untrastructural morphology was observed by TEM. PEDF expression was examined by immunohistochemistry. And FCM analysis was used to identify the kinetic variation of the peripheral T cell population and CD4+/CD8+ ratio. Results: 1. The mean survival time of the allografts in the experimental group was 22.564±0.321 days , but the mean survival time of the control group was 12.125±0.313 days ,which was obviously longed as compared with the control group (P<0.05). 2. The area of CNV was inhibited by 1 week,2 weeks,3 weeks,1 month and 2 months(P﹤0.01 or P﹤0.05). 3. The rejection index of the experimental group was lower obviously than the control group by 1 week,2weeks,3weeks,1 month and 2 months(P﹤0.01 or P﹤0.05). 4. Significantly increased PEDF expression was also observed in the experimental group compared with the control group by immunohistochemistry staining. 5. In comparing with the control group, the peripheral CD4+ cells and CD4+/CD8+ in the experimental group were decreased significantly. Conclusions: 1. Topical application of PEDF eyedrops can prolong survival time of the allografts.2. The area of CNV was decreased by topical application of PEDF eyedrops and PEDF can prevent vascular growth of corneal allografts. 3. Topical application of PEDF eyedrops suppressed effectively the postoperative corneal allograft rejection according to the rejection index. 4. PEDF eyedrops can enhance PEDF expression in corneal allografts. 5. The peripheral T cell activation was inhibited and the CD4+/CD8+ ratio decreased obviously by the application of PEDF eyedrops. |
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