Histological and ultrastructural features for proliferation inhibition by delivery of exogenous p27Kip1 to rabbit models after glaucoma filtration surgery.

PURPOSE: To investigate postoperative inhibition of cell proliferation in animals treated with exogenous p27Kip1 during an experimental glaucoma filtration surgery (GFS) by histological and ultrastructural examinations.

METHODS

The primer was designed according to p27Kip1 gene sequence of GenBank. The p27Kip1-expressing adenovirus-mediated Ad-p27 was constructed according to standard techniques. Gene therapy was performed by subconjunctival delivery of Ad-p27, mitomycin C (MMC) and PBS served as controls. Histological and ultastructural changes at surgical sites were observed for 28 days postoperatively.

RESULTS

Histologically, evident cellular proliferation induced by Ad-p27 was observed on day 7, with appreciable filtering cavity. However, thin conjunctival layers were noted, and the number of fibroblasts decreased in the Tenon's capsule on day 14. On day 28, the filtering cavity partially disappeared. The histological features of the animals with MMC delivery were similar to those treated by Ad-p27. In contrast, in the PBS treatment group, thick conjunctival layers were observed, and the number of goblet cells and fibroblasts, increased markedly. The filtering cavity disappeared at postoperative day 21. Twenty eight day postoperatively, ultrastructural findings showed that most conjunctival epithelial cells in the Ad-p27 treatment group were under static state, and that organelles were inactive. The number of goblet cells, and the secretion of mucin, were decreased. The amount of fibroblasts also decreased with partial apoptotic cells. The ultrastructural features presented by rabbits with the MMC delivery resembled those treated with Ad-p27. In the PBS treatment group, the number of conjunctival epithelial cells increased; the amount of goblet cells increased as the secretion of mucin was strengthened, and a substantial amount of fibroblasts were observed with active and productive organelles.

CONCLUSION

Ad-p27 inhibits the proliferation of Tenon's capsule fibroblasts at surgical sites, and suppresses the formation of scars, thereby promoting surgical efficacy.