[Amniotic membrane transplant using fibrin glue for the treatment of deep layer corneal damage]

To treat deep layer corneal damage using fibrin glue and amniotic membrane transplant.

Forty-five rabbits were given deep lamellar keratectomies to cause deep layer corneal damage in their right eyes and were then randomly divided into 3 groups. The first group was given double-layer amniotic membrane transplants where fibrin glue was used to connect the two layers of amniotic membrane. The second group was given double-layer amniotic membrane transplants where no fibrin glue was used. The third group was given no treatment. Clinical outcome was graded by corneal integrity, opacity and neovascularization, and detachment of amniotic membrane was recorded. The expression of apoptosis was monitored to assess the changes of morphology and histology on the 7th, 14th and 28th days after surgery.

While the double-layer amniotic membrane without fibrin glue covered the cornea for (13.15 ± 2.68) d, the double-layer amniotic membrane using fibrin glue covered the surface of the cornea for (20.00 ± 2.43) d (t = 8.470, P = 0.000). The corneas in the first group recovered smoothly and transparently, maintained normal thickness and less neovascularization, whereas the corneas in the other two groups recovered irregularly, lost their transparency, became turbid and showed higher levels of neovascularization. There were statistically significant differences between the first and third groups for corneal opacity and neovascularization, where the 14th day after surgery, the first group scored 2.62 and the third group scored 5.19 (t = 3.986, P = 0.004), and the 28th day after surgery, the first group scored 2.87 and the third group scored 4.78 (t = 3.608, P = 0.007). Perforation did not appear in the first group, but the second group had 3 cases and the third group had 2 cases, all due to infection. The changes of morphology and histology showed that the damaged corneas were contained normal epithelial cells and regularly arranged fibrous cells on the 28th day after surgery. The apoptosis in corneas of the first group was less than that of the third group at all observed points (7th day: t = 8.153, P = 0.000; 14th day: t = 9.693, P = 0.000; 28th day: t = 14.050, P = 0.000), however, apoptosis in corneas in the second group was only different from that in the third group on the 7th day after surgery while other observed points showed no difference (7th day: t = 5.474, P = 0.000).

Using bio-engineered fibrin glue in amniotic membrane transplants can repair deep layer corneal damage, reduce neovascularization, scarring and corneal apoptosis.