负载曲安奈德水凝胶缓释片在兔眼微创小梁切除术中的抗瘢痕作用

目的：研究负载曲安奈德(TA)的水凝胶缓释片在兔眼“单步隧道法”新型微创小梁切除术(SIGS)中的抗瘢痕作用及其安全性。

方法：选择健康新西兰大耳白兔48只，随机分为四组(每组12只)，小梁切除术组(Trab组)、SIGS组、在SIGS术中结膜瓣下植入聚乙烯醇水凝胶(PVAH)薄片(PVAH组)、在SIGS术中结膜瓣下植入负载TA的水凝胶缓释片(TA/PVAH组)。分别于术后1、2、3、4 wk观察并记录各组眼压、滤过泡形态、前房反应及其它并发症情况，并处死动物，取右眼术区组织行病理组织石蜡切片，并行Masson染色、苦味酸-天狼星玫瑰红染色及α-平滑肌肌动蛋白(α-SMA)、纤维细胞生长因子-2(FGF2)免疫组化染色。观察局部组织炎性细胞浸润情况、成纤维细胞增殖及Ⅰ型、Ⅲ型胶原纤维合成情况，计算并比较各组α-SMA、FGF2抗体免疫组化染色的平均阳性面积比。

结果：术后2 wk TA/PVAH组均保持了弥散隆起的功能性滤过泡，而Trab组、SIGS组和PVAH组均有术眼出现扁平滤过泡。术后4wk，PVAH组、TA/PVAH组分别有1眼(33%)、2眼(67%)存在功能性滤过泡，其余滤过泡均扁平。Masson染色显示：术后4 wk PVAH组和TA/PVAH组水凝胶均未降解，相对于Trab组和SIGS组，滤过道更为明显，有较少胶原纤维增生。天狼星红染色显示：术后4 wk，与Trab组、SIGS组和PVAH组相比，TA/PVAH组的Ⅰ型胶原和Ⅲ型胶原的表达更少。免疫组化染色显示：术后1 wk，TA/PVAH组α-SMA表达较Trab组和SIGS组均明显降低(P<0.01)； 术后2 wk Trab组和SIGS组α-SMA表达最高，而PHAP组和TA/PVAH组结膜组织中α-SMA表达较前两组均显著降低(P<0.01)。与Trab组相比， PVAH组、TA/PVAH组术后1、2、3、4 wk FGF2表达均明显升高(P<0.05)； 与SIGS组相比，TA/PVAH组术后4 wk FGF2表达明显升高(P<0.05)。

结论：兔眼SIGS术中联合结膜瓣下填充负载TA的水凝胶缓释片能有效抑制手术区滤过道瘢痕化，可能是TA抗瘢痕作用与水凝胶支架作用的共同结果。

Anti-scarring effects of triamcinolone acetonide-loaded hydrogel sustained-release sheeting on stab incision glaucoma surgery in rabbit

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.