Objective: To study the cell membrane of corneal endothelium with a micromolecular compound J2 in corneal allograft of rat using atomic force microscopy (AFM).
Methods: Cohort study. Subjects were divided into two groups: group A (n = 15): experimental group; group B (n = 15): placebo control group. At the fifth, tenth, fifteen, twentieth, twenty-fifth day after penetrating keratoplasty, the donor implant was separated from receipt bed, one part of which was stained by HE and the others fixed into AFM sample. Amplitude and height images were obtained in the tapping mode with a scan rate of 2 Hz and an integral gain of 0.3 to 0.5. Statistical analysis was performed using single-factor analysis of variance and P value was calculated.
Results: The average transplant survival time in group A was (33.12 ± 6.80) d, and those in group B was (18.87 ± 4.19) d. There were significant difference between two group (F = 47.7449, P = 0.00). There were obvious differences on ultrastructure measured by AFM between two groups. At the fifth day after penetrating keratoplasty, regular hexagonal structure of corneal endothelium was observed by AFM in both two group. The diameter of corneal endothelium was about 15 µm, uneven microstructure of cell could be found. The time being, different changes were arose in two group: a clear microstructure could be found in group A, however the microstructure of cell could not be recognized in group B. One way analysis of variance showed that significant differences on parameters (Ra, Rp and Rv) were found between two groups (P < 0.05). At the fifth day after penetrating keratoplasty, group A: Ra (97.64 ± 31.58) nm, Rp (297.79 ± 25.19) nm, Rv (545.55 ± 25.83) nm; group B: Ra (112.61 ± 34.29) nm, Rp (265.06 ± 24.17) nm, Rv (544.41 ± 21.78) nm (Fa = 30.9416, P = 0.0000; Fp = 263.6018, P = 0.0000; Pv = 1.2013, P = 0.2735). At the tenth day after penetrating keratoplasty, group A: Ra (102.98 ± 32.98) nm, Rp (711.38 ± 21.94) nm, Rv (639.89 ± 22.58) nm; group B: Ra (222.85 ± 31.28) nm, Rp (111.22 ± 20.35) nm, Rv (746.49 ± 23.17) nm (Fa = 2086.4535, P = 0.0000; Fp = 53768.4676, P = 0.0000; Pv = 3257.3178, P = 0.0000). At the fifteenth day after penetrating keratoplasty, group A: Ra (87.44 ± 34.97) nm, Rp (344.18 ± 21.09) nm, Rv (482.61 ± 22.27) nm; group B: Ra (197.64 ± 35.72) nm, Rp (510.76 ± 24.98) nm, Rv (545.62 ± 23.17) nm (Fa = 1458.1057, P = 0.0000; Fp = 7788.6963, P = 0.0000; Pv = 1153.2860, P = 0.0000). At the twentieth day after penetrating keratoplasty, group A: Ra (85.85 ± 32.53) nm, Rp (348.69 ± 21.26) nm, Rv (367.65 ± 23.12) nm; group B: Ra (201.36 ± 34.12) nm, Rp (788.58 ± 20.34) nm, Rv (563.33 ± 21.01) nm (Fa = 1801.1215, P = 0.0000; Fp = 67 057.9516, P = 0.0000; Fv = 11 770.2195, P = 0.0000). At the twenty-fifth day after penetrating keratoplasty, group A: Ra (104.97 ± 32.47) nm, Rp (395.05 ± 20.38) nm, Rv (396.17 ± 21.59) nm; group B: Ra (43.85 ± 31.28) nm, Rp (249.88 ± 20.79) nm, Rv (154.88 ± 22.37) nm (Fa = 551.4134, P = 0.0000; Fp = 7458.9255, P = 0.0000; Pv = 18 070.5189, P = 0.0000).
Conclusions: The morphology and ultrastructure of corneal endothelium in group A with J2 were different from group B by observation with AFM. J2 was an effect micromolecular in prevention of corneal allograft rejection.