Clinical And Fundamental Study Of Non-Penetrating Trabecular Surgery

Purpose: Compared with trabeculectomy, non-penetrating trabecular surgery provides fewer early postoperative complications and quickly recovered vision. But the problem of fibrosis and the mechanism of aqueous outflow pathways after non-penetrating trabecular surgery is needed to study, so the purpose of the research work is to investigate :1. evaluate the effectiveness and safety of non-penetrating trabecular surgery with the use of 0.1mg/ml mitomycin C. 2. investigate the effect of 0.5% tranilast eye drops on alpha 2( â… ) procollagen and transforming growth factor-β₁ (TGF-β₁)mRNA expression in rabbit Tenon's capsule. 3. study the morphological findings and aqueous outflow pathways after non-penetrating trabecular surgery.Materials and method: 1. 30 eyes of 21 patients with open angle glaucoma were divided into 2 groups randomly. In 20 eyes of 14 patients (group â…  ) a sponge soaked with MMC(0.1mg/ml) was applied for 5 minutes in the scleral bed, and in 10 eyes of 7 patients (group â…¡) a reticulated hyaluronic acid implant was sutured in the scleral bed. The mean follow-up period was (30.35±8.89) months (12 to 51 months). The postoperative visual acuity, intraocular pressure (IOP), filtering blebs and complications in the two groups were compared.2. Fifteen rabbits were randomly divided into three groups: group tranilast, group vehicle solution and un-treated control group. Alpha 2( â… ) procollagen and TGF-β₁ mRNA in rabbit Tenon's capsule and scar tissue were detected by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis.3. Twelve rabbits were randomly divided into experimental group and un-treated control group. Non-penetrating trabecular surgery was performed on rabbits' eyes of experimental group. At days 1, 14 and 30 after surgery, three rabbits were randomly choosed to receive intracameral injection of horseradish peroxidase(HRP) in one eye and tetramethylrhodamine-dextran(TMR-D) in the other eye. After survival time of 60min, the experiments were terminated by carotid artery perfusion with fixative. The eyes were enucleated and freeze sections were prepared to observe tracer's distribution. The same method of tracer's intracameral injection was performed in un-treated control group.Result: 1. (1) Visual acuity: The visual acuity at postoperative 1 month was not significantly different between group â…  and â…¡ (P=0.220). (2) IOP: At postoperative 6,12, and 24 months, the mean IOPingroup â…  was (15.40±3.51)mmHg,(15.24±3.10)mmHg,(15.48±2.69)mmHg and that in group â…¡ was (16.65±2.50) mmHg, (16.29±2.92) mmHg, (17.22±2.06) mmHg respectively. The mean IOP at postoperative 6 , 12, and 24 months was not significantly different between the two groups (t=0.956,0.853,1.665 P=0.348,0.402,0.110). At postoperative 24 months, the life-table complete success rates of group â…  and â…¡ were 78.89% and 55.60%. With medication and (or) Nd:YAG laser goniopuncture, the qualified success rates were 89.47% and 88.89% in group â…  and â…¡. There were no statistical difference in complete and qualified success rates between the two groups (Log-Rank test: x²=1.076, 0.0002, P>0.05). (3) filtering blebs: 16 eyes (84.21%) in group â…  and 6 eyes (66.67%) in group â…¡ had micro-sac or diffuse blebs. There was no difference in the category of blebs between the two groups (P=0.216).(4) Complications: In group â… , there were 5 eyes with minimal anterior chamber reaction and 2 eyes with a small quantity of hyphema. In group â…¡, there was one eye with minimal anterior chamber reaction. (4) Gonioscopy: peripheral anterior synechiae to the non-penetrating trabecular meshwork could be observed in 3 eyes of group I and 2 eyes of group â…¡.2. The value of alpha 2( I ) procollagen/B-actin was 0.880±0.029,1.034±0.065, 0.808±0.041 for group tranilast, group vehicle solution and un-treated control group respectively. The difference between groups was statistically significant(f=4.808,3.207,6.551, P<0.05). The value of TGF-Bi/G3PDH was 0.894±0.058, 0.882±0.090, 0.852±0.061 for group tranilast, group vehicle solution and un-treated control group respectively. Though the value of group tranilast and group vehicle solution was higher than un-treated control group, the difference between groups was not statistically significant(f=0.934, 0.667,0.267, P> 0.05).3. At days 1 and 14 after surgery in experimental group, intense HRP label was seen in filtration bleb and the canal under the scleral flap. At 14 days after surgery, fibrous tissue was not found in the canal, HRP staining was observed in the sclera adjacent to the dissection site. At 1 month after surgery, HRP staining was weakened and fibrous tissue proliferation was found in the canal. In control group, feeble HRP staining was present in conjunctiva, but no HRP granules in sclera. Fluorescence was found in choroidal tissue of both experimental group and control group.Conclusion: 1. In our study, the clinical effectiveness of NPTS with O.lmg/ml MMC is similar to that of NPTS with reticulated hyaluronic acid implant. But the former lessens the patients' burden greatly for it's low cost. 2. 0.5% tranilast eye drops could inhibit alpha 2( I ) procollagen mRNA expression in rabbit Tenon's capsule and scar tissue. It can be used as an anti-scarring drug after non-penetrating trabecular surgery. 3. In the present study, aqueous outflow pathways after NPTS involve subconjunctival filtration, interscleral absorption and uveoscleral outflow.