Abstract: Objective To investigate the preventing effect of cyclosporine A nano-particle eye drops on immune rejection after high risk corneal transplantation. Design Experimental study. Participants Fifty Lewis rats as receptor and twenty-five F344 rats as donator. Method Corneal neoangiogenesis was induced by suture method. Rats were divided into 5 groups(group A to E). All the animals underwent corneal penetrating transplantation in right eyes at 7th day after suturing when the new vascular appeared in the middle part of the cornea. The cornea donator were F344 rats. Group A received vehicle eye drops, group B received cyclosporine A eye drops, group C to E received 0.5%, 1% and 2% cyclosporine A nano-particle eye drops respectively. All animals were received the eye drops 3 times a day. Cornea was observed by slit lamp everyday within 14 days and photographs were taken.  Then the cornea was observed every two days until 28 days. The cornea was studied pathologically at day 14 for 2 rats each group.  Main Outcome Measures Cornea survival time (from corner transplantation to the time when RI equals 6), rejection index (RI), pathologically observation of cornea at day 14. Results The mean survival time from group A to E were 7.20±2.93 days, 10.89±3.62 days, 10.50±3.40 days, 11.13±3.94 days and 12.80±4.07 days respectively. Significant difference was found among groups (F=3.20, P=0.022). The survival time at any group from B to E was significantly longer than group A(P  value was 0.031, 0.047, 0.027, 0.001 respectively).  No significant difference was found between group B and any group from C to E (P  value was 0.815, 0.853, 0.255 respectively). No significant difference was found between group C and group D or group E (P  value was 0.716, 0.161 respectively). No significant difference was found between group D and group E (P = 0.333). RI from group A to E were 7.80±1.48, 5.67±1.80, 6.10±1.66, 5.25±1.75 and 4.80±1.23 respectively. Significant difference was found between them (F=5.202, P=0.002). The RI at any group from B to E was lower than group A (P  value was 0.005, 0.021, 0.002, 0.000 respectively). No significant difference was found between group B and any group from C to E(P  value was 0.555, 0.592, 0.241 respectively). No significant difference was found between group C and group D or group E(P value was 0.265, 0.074 respectively). No significant difference was found between group D and group E (P=0.553). The cornea was obviously edematous, thickening, and showing cell infiltration in group A. The cornea cells showed layer disorder in group A. The degree of cornea infiltration was lighter in group B to E than in group A. Conclusion  Cyclosporine A nino-particle eye drops of high, middle, low concentration and ordinary Cyclosporine A eye drops can effectively prevent cornea immune rejection after high risk cornea transplantation. (Ophthalmol CHN, 2012, 21: 116-120)

Key words: corneal transplantation, immune rejection, cyclosporine A, nano-particle eye drops