AIM:To observe the anti-scarring effects and safety of triamcinolone acetonide(TA)-loaded hydrogel sustained-release sheeting on stab incision glaucoma surgery(SIGS)with “one-step tunnel method” in rabbit eyes.

METHODS:A total of 48 healthy New Zealand white rabbits were randomly selected and divided into 4 groups(12 rabbits in each group), trabeculectomy(Trab)group, SIGS group, polyvinyl alcohol hydrogel(PVAH)sheeting was implanted under the conjunctiva flap during SIGS(PVAH group), and hydrogel sustained-release sheeting loaded with TA was implanted under the conjunctiva flap during SIGS(TA/PVAH group). On the 1, 2, 3, and 4 wk after surgery, the intraocular pressure, filtering bubble morphology, anterior chamber reaction, and other complications were observed and recorded in each group. Then animals were euthanized, and the surgery area tissues of right eye were taken for pathological tissue paraffin section. Masson staining, picric acid-Sirius rose red staining, as well as α-smooth muscle actin(α-SMA)and fibroblast growth factor 2(FGF2)immunohistochemistry staining was performed on every section. The infiltration of inflammatory cells, proliferation of fibroblasts and synthesis of type I and type III collagen fibers in local tissues were observed. The average positive area ratio of α-SMA and FGF2 antibody immunohistochemical staining in each group was calculated and compared.

RESULTS: The TA/PVAH group maintained diffuse and elevated functional filtering blebs, while flat filtering blebs appeared in Trab, SIGS and PVAH groups at 2 wk after surgery. Functional filtering blebs were present in 1 eye(33%), 2 eyes(67%)in the PVAH and TA/PVAH group at 4 wk after surgery, respectively, while the other filtering blebs were flattened. Masson staining showed that the hydrogels in PVAH and TA/PVAH groups did not degrade at 4 wk after surgery. Compared with the Trab and SIGS groups, the filtration passages were more obvious, with less collagen fiber proliferation. Sirius red staining showed that the expression of type I collagen and type III collagen in the TA/PVAH group was less than that in the Trab group, SIGS group and PVAH group at 4 wk after surgery. Immunohistochemical staining showed that the α-SMA expression in the TA/PVAH group was significantly lower than that in the Trab and SIGS groups at 1 wk after surgery(P<0.01). The α-SMA expression was the highest in the Trab and SIGS groups at 2 wk after surgery, while the α-SMA expression in the PHAP and TA/PVAH groups was significantly lower than that in the first two groups(P<0.01). Compared with the Trab group, the expression of FGF2 in the PVAH and TA/PVAH group was significantly increased at 1, 2, 3 and 4 wk after surgery(P<0.05). Compared with the SIGS group, FGF2 expression in the TA/PVAH group was significantly increased at 4 wk after surgery(P<0.05).

CONCLUSION:In SIGS surgery of rabbit eyes, implanting hydrogel sustained-release sheeting loaded with TA under conjunctival flap can effectively inhibit the scarring of the filtering bleb, which may be the interaction of the anti-scar effect of TA and the stent function of hydrogel.