| Purpose:To evaluate the effect and safety of subconjectival three different doses of Avastin on antifibrosis after experimental glaucoma filtering surgery in rabbits, and discuss the time and dosage of subconjunctival Avastin.Methods:50 eyes of 50 rabbits, undergoing trabeculectomy, were randomly divided into five groups:experimental group A(0.5mg Avastin), experimental group B(1.0mg Avastin), experimental group C(2.0mg Avastin), mitomycin C(MMC) control group, and blank control group. Experimental groups A,B,C were separately subconjunctival injected with 0.08ml Avastin of three different concentrations(6.25mg/ml,12.50mg,25.0mg/ml) when trabeculectomy finished and on the 3rd,7th day after surgery; In the MMC control group, MMC cotton patch(0.2 mg/ml) was put under the capsule Tenons and scleral flap during operation; blank control group were subconjunctival injected 0.08ml 0.9% sodium chloride solution when trabeculectomy finished and on the 3rd,7th day after surgery. The appearance of filter bleb were observed after surgery, and examined using an living confocal microscopy; IOP was measured; on the 7th,14th day after surgery,5 eyes of each group were performed histopathologic examination, Tunel cell apoptosis examination, and TGF-β1,bFGF content test with ELISA.Result:(1) Slit lamp microscopy examination:On the postoperative 7th day, elevated and diffused filter blebs with few vessels could be seen clearly in three experimental groups and MMC group; in the blank control group, bleb started becoming limited on the postoperative 3rd day, and there were many vessels arround scarring bleb on the postoperative 7th day. On the postoperative 14th day, blebs were flatter and more diffused, with fewer vessels in experimental group C and MMC group than other groups; in experimental group B, blebs were also flat and diffused, but with more vessels than that on the 7th day; blebs becamed scarred and vascularization in both group A and group E. (2) IOP:IOP within 14 days after surgery in each group were increasesed linearly, and the growth trend is similar. There were also no difference among five groups at different time points. (3) Living confocal microscopy:On the postoperative 7th day, there were more significant bleb cavities, thinner and looser fibrous tissue in three experimental groups and MMC group than the blank control group; a large number of inflammatory cells can be seen in MMC control group. On the postoperative 14th day, experimental group C and MMC group still showed obvious bleb cavities and loose fibrous tissue; in experimental group B, a little bleb structure still remained; and bleb structure disappeared and fibrosis was serious in other groups. (4) Histopathologic examination:Filter blebs could be seen clearly in each group on the postoperative 7th day. And on the postoperative 14th day, filter blebs, were larger in experimental group C and MMC control group than other groups; there were only some small blebs in experimental group B; and in experimental group A and blank control group, filter blebs disappeared, and marked hyperplasia of fibrous tissue could be seen. Image analysis showed:On the postoperative 7th day, there was no significant difference about the percentage of the bleb cavity surface area in the conjunctiva and the percentage of bleb-forming region in the conjunctiva. On the postoperative 14th day, the percentage of the bleb cavity surface area in the conjunctiva of experimental group C and MMC group were significantly higher than other groups, the percentage of the bleb cavity surface area of experimental group B was higher than experimental group A and blank control group, and there were no significant difference between experimental group C and MMC group and between experimental group A and blank control group on the filtering bleb area percentage. The percentage of bleb-forming region in the conjunctiva of experimental group C and MMC control group were significantly higher than other groups, but there were no significant difference between experimental group C and MMC control group and among experimental group A, B and blank control group on the filtering bleb area percentage. (5) ELISA:On the postoperative 7th,14th day, the content of TGF-β1 and bFGF in the humor aqueous and surgery area organization were lower in experimental group C and MMC group than other groups; the content of TGF-β1 and bFGF in experimental group B were lower than experimental group A and blank control group, but there were no significant difference between experimental group C and MMC group and between experimental group A and blank control group. (6) Tunel cell apoptosis examination: On the postoperative 7th,14th day, the number of apoptosis cells in the MMC control group was more than other groups; there were no difference among three experimental groups and blank control group.Conclusion:Subconjunctival injection of 2.0mg and 1.0mg Avastin can inhibit bleb angiogenesis, help alleviating the bleb scarring, promote functional bleb formation and maintenance. It is safe and effective.
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