Trabeculectomy In Rabbits Research Articles

Topical Administration of Bevacizumab to Facilitate the Functional Filtering Bleb After Trabeculectomy in the Rabbit.

Purpose: To evaluate the effects of bevacizumab in 3 different application methods, subconjunctival injection (SCI), hyaluronic acid retardant (HAR), and eye drop (ED), on attenuating scar formation in the filtering bleb. Methods: Trabeculectomy (TRAB) was performed on New Zealand rabbits. TRAB rabbits were intervened with bevacizumab SCI, HAR, ED, or mitomycin C, respectively. Intraocular pressure (IOP) of 1, 7, 14, and 28 days after TRAB was recorded, and the bleb survival rate was analyzed. Bleb height, area, and vascularization were evaluated using anterior segment optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) at 7, 14 and 28 days after surgery. A histopathology examination of the bleb tissue was performed. The expression levels of vascular endothelial growth factor (VEGF)-A, interleukin (IL)-1α, tumor necrosis factor-alpha (TNF-α), transforming growth factor-β1 (TGF-β1), and α-smooth muscle actin (α-SMA) were measured by Western blot. Results: Bevacizumab significantly reduced postoperative IOP and increased the survival of the filtering bleb, especially in the ED group. Less vascularization was shown in the SCI, HAR, and ED groups. Histopathological results showed the fewest levels of scarring and fibrosis in the ED group. The local VEGF-A, IL-1α, and TNF-α expression levels after bevacizumab ED were decreased, combined with suppression of TGF-β1 and α-SMA. Conclusions: Postoperative use of bevacizumab EDs was an effective application method for improving surgical outcomes after TRAB in rabbits. It might be effective in preventing scarring of the filtering bleb by antivascularization and anti-inflammation.

Inhibition of Type I Collagen Expression in Fibrosis Prevention after Trabeculectomy: Oryctolagus cuniculus

The administration of postoperative bevacizumab injection in subconjunctival trabeculectomy will reduce bleb fibrosis. This study aimed to investigate the effect of bevacizumab as an antifibrotic agent on collagen density, collagen thickness and type I collagen expression after trabeculectomy in rabbits. Sixteen males New Zealand white rabbits were divided into two groups, control and treatment group. Masson’s trichrome was performed to evaluate collagen density and thickness. Immunohistochemistry examination using a monoclonal antibody to type I collagen was performed to evaluate collagen expression. Among the sixteen samples, postoperative bleb conditions obtained diffuse bleb, and there were no differences in bleb characteristics between the control and treatment groups. Anterior chamber was deep, and cornea was clear in all animals. This study showed that the density of collagen fibers and type 1 collagen expression significantly decreased in the treatment group compared to control group (p = 0.0075; p = 0.006, respectively). However, there was no significant difference in the thickness of collagen fibers in both groups (p = 0.323). Bevacizumab reduces bleb fibrosis by inhibition of angiogenesis and accumulation of extracellular matrix. Postoperative subconjunctival injection of bevacizumab may limit scar tissue formation at the site of trabeculectomy by blocking collagen synthesis.

The effectiveness of colchicine combined with mitomycin C to prolong bleb function in trabeculectomy in rabbits.

PurposeTo investigate the potential of colchicine to improve bleb function after trabeculectomy.MethodsTo find the maximum usable colchicine concentration, an ocular irritation study was performed with the Draize test at concentrations of 0.001%, 0.01% and 0.1%. Additionally, the synergistic effect of topical colchicine instillation and MMC application to surgical site was evaluated in a rabbit model by measuring changes after trabeculectomy in intraocular pressure (IOP) and bleb morphology score at 3, 7, 14, 21, 28, 35, 42, and 49 days.ResultsExperiments with a rabbit model of trabeculectomy showed that 0.04% MMC plus 0.01% colchicine was more effective than saline and 0.04% MMC alone in maintaining IOP reduction at days 7–49 (P < 0.01 at all time points) and day 49 (P < 0.05), respectively, while 0.04% MMC alone was more effective than saline only at days 7–35 (P < 0.05 at all time points). 0.04% MMC plus 0.01% colchicine and 0.04% MMC alone were more effective than saline at preserving bleb score at days 7–21 and 35–49 (P < 0.05 at all time points) and at days 7–35 (P < 0.05 at all time points), respectively.ConclusionColchicine may be a promising adjuvant for strengthening the effect of MMC and improving the survival of the filtering bleb in trabeculectomy.

Inhibitory effects of bevacizumab on filtering bleb scarring following trabeculectomy in rabbits

Background The primary reason to trabeculectomy failure is fibrosis of conjunctiva and episclera because of progressive fibroblast proliferation and collagen deposition of the filtration bleb.Conventional methods of inhibiting bleb scarring was intraoperative application of mitomycin C (MMC), but many complications occured after surgery.Researches showed that bevacizumab was an antifibrotic agent, and whether it can suppress scarring of filtering bleb after trabeculectomy is concerned. Objective The aim of this study was to evaluate the antifibrotic efficacy of bevacizumab after trabeculectomy in rabbits. Methods Forty New Zealand rabbits were randomly divided into four groups.Trabeculectomy was performed on the right eyes of each rabbits.The rabbits received subconjunctival injection of 0.05 ml bevacizumab (25 mg/ml) at the end of operation in the bevacizumab single injection group.The same dose of bevacizumab was respectively injected at the end of operation as well as 3 days and 7 days after operation in the bevacizumab repitition injection group, and 0.05 ml normal saline solution was used in the same way in the normal saline group.In the MMC group, MMC cotton patch with 0.2 mg/ml was placed under the Tenon caplsule and scleral flap for 3 minutes during operation.The intraocular pressure (IOP), bleb area and shape were evaluated during the 28-day period.The animals were sacrificed on postoperative day 14 and 28, respectively for the histopathologic examination of bleb.The expression of CD31 in the bleb was detected by immunohistochemistry for the calculation of microvessels.All experiments were performed in accordance with the ethics code for animal experimentation and approved by the Institutional Review Board of Tianjin Eye Hospital. Results No significant difference was found in the postoperative IOP among the groups (F=0.88, P=0.47). Compared with the bevacizumab single injection group, MMC group and normal saline group, the shape of bleb was higher and much diffuse with sparse vessels 7 days after operation in the bevacizumab repitition injection group.The survival time of bleb was 27 days, 19 days and 13 days in the bevacizumab repitition injection group, the bevacizumab single injection group, MMC group and normal saline group, respectively.The percentage of collagen deposition area was (49.18±1.54)%, (26.41±1.23)%, (50.68±1.87)% and (70.63±1.81)% at day 14 postoperative in the bevacizumab single injection group, bevacizumab repitition injection group, MMC group and normal saline group, respectively, with the largest area in the normal saline group, and percentage of collagen deposition area was significantly reduced in the bevacizumab repitition injection group compared with the bevacizumab single injection group (all at P<0.05). The percentage of collagen deposition area was (66.82±1.53)% at day 28 postoperative in the bevacizumab repitition injection group, while complete scarring was seen in other 3 groups.The number of microvessels was least at postoperative day 14 in the bevacizumab repitition injection group compared with the bevacizumab single injection group, MMC group and normal saline group (all at P<0.05). The number of microvessels was more in postoperative day 28 in the bevacizumab repitition injection group (3.51±0.31) compared with other groups (all at P<0.05). Conclusions Subconjunctival injection of bevacizumab following trabeculectomy can improve the successful rate of surgery by remaining the survival time of filtering bleb, inhibiting the bleb scarring in rabbits. Key words: Antibodies, monoclonal, humanized; Bevacizumab; Conjunctiva/pathology; Disease models, animal; Fibrosis/prevention c Glaucoma/surgery; Trabeculectomy; Wound healing/drug effects

Anti-scarring effects of triamcinolone acetonide/polylactic acid caprolactone drug-loaded electrospinning film with trabeculectomy in rabbits

Background Scarring of filter bleb is a main cause of failure after trabeculectomy.Administration of anti-proliferation dugs during filtering surgery can maintain the opening of filtering pathway, but some serious complications occure after the drug use.Researches showed that polylactic acid caprolactone (PLCA) drug-loaded electrospinning film can release drug slowly, but its application in glaucoma is seldom. Objective The aim of this study was to evaluate the anti-scarring effects of non-penetrating trabeculectomy combined with sclera interlayer implantation of triamcinolone acetonide (TA)/PLCA drug-loaded electrospinning film in rabbit. Methods TA/PLCA drug-loaded electospinning film was prepared by electrospinning and its surface ultrastructure was observed under the scanning electron microscope.The drug release properties were detected by high performance liquid chromatograph.Ocular hypertensive models were established in New Zealand white rabbits by injecting carbomer into the anterior chamber of the right eyes, and the 40 models were randomized into 5 groups, 8 eyes for each group.TA/PLCA drug-loaded electrospun membrane, PLCA electrospun membrane or amniotic membrane was implanted beneath the scleral flap during trabeculectomy respectively in the TA/PLCA group, PLCA group or amniotic group, and 40 mg/ml TA was subconjunctivally injected in the TA group.Only trabeculectomy was performed in the simple trabeculectomy group.Intraocular pressure (IOP) was measured, and the shape of filtering bleb was examined under the slit lamp 1 week, 2, 4, 8 and 12 weeks after surgery.The section of filtering bleb was prepared 12 weeks after surgery for the histopathological examination.The use and management of experimental animals was in line with animal ethics. Results The similar three-dimensional reticular structure was seen between TA/PLCA and electrospun membrane with the fiber diameter 0.5-1.5 μm.TA was released stably for 14 days.All the filtering blebs were disappeared in the simple trabeculectomy group during 8-week duration after operation.At 12 weeks after operation, the functional bleb was found in all the 8 eyes of the TA/PLCA group, 5 eyes of PLCA group, 4 eyes of the amniotic group and 4 eyes of the TA group.The IOP was significantly different among the groups, with the lowest IOP in the TA/PLCA group and the highest IOP in the simple trabeculectomy group (all at P=0.000). Histopathological examination showed that the filtering pathway remained opening in all 8 eyes with the epithelization of bleb surface in the TA/PLCA group, and interspaces of the filtering pathway was explayed in the PLCA group, amniotic group and TA group, while fibrosis of filtering pathway was seen in the simple trabeculectomy group at 12 weeks after surgery. Conclusions TA/PLCA drug-loading electrospun membranes presents with nanoscale microstructure and good drug-release properties in vitro.Implantaion of TA/PLCA beneath the scleral flap during trabeculectomy can inhibit the fibrosis of filtering pathway. Key words: Glaucoma/therapy; Trabeculecutomy; Polylactic acid caprolactone/chemistry; Triamcinolone acetonide/pharmacology; Proliferation; Drug delivery systems; TA/PLCA drug-loaded electrospinning film; Rabbits

Clinical outcomes of amniotic membrane loaded with 5-FU PLGA nanoparticles in experimental trabeculectomy.

To evaluate the effect of amniotic membrane loaded with 5-fluorouracil poly (lactic-co-glycolic acid) (PLGA) nanoparticles (5-FU-NPs) in the surgical outcomes of experimental trabeculectomy in rabbits. Thirty-two New Zealand white rabbits were randomly categorized into four groups with 8 rabbits in each group. Group 1, the control group, performed traditional trabeculectomy without adjuvant treatment. While the experimental groups performed compound trabeculectomy with different implantations including amniotic membrane (group 2), 5-FU-NPs (group 3) and amniotic membrane loaded with 5-FU-NPs (group 4). Clinical evaluations including IOP measurement and filtration bleb analysis were performed in all groups postoperatively. There is no significant difference of mean IOP in all groups at first 7d after surgery. While at P14, mean IOPs of experimental group 2 (9.8±2.1 mm Hg), groups 3 (8.9±2.8 mm Hg) and group 4 (7.6±2.3 mm Hg) were significantly reduced compared to control group (12.4±2.6 mm Hg; n=8, P<0.05). At P21, mean IOPs of groups 3 (11.7±3.2 mm Hg) and group 4 (9.9±1.6 mm Hg) were significantly decreased compare to control group (17.9±1.6 mm Hg) and group 2 (16.6±2.8 mm Hg; n=8, P<0.05). At P28, mean IOPs of groups 3 (13.8±3.3 mm Hg) and group 4 (10.6±2.0 mm Hg) were also significantly reduced compare to control group (19.4±2.3 mm Hg) and group 2 (18.5±2.4 mm Hg; n=8, P<0.05). Meanwhile mean IOP of group 4 is significantly decreased compared to group 3 at P28 (n=8, P<0.05). Survival analysis of functional filtration blub in all groups revealed the longest survival time in group 4 (24.9±5.1d) compared to that in group 3 (20.6±4.3d), group 2 (15.0±5.2d) and control group (10.1±5.7d). Amniotic membrane loaded with 5-Fu-NPs may function as an effective anti-scarring implant and provides improved long-term surgical outcomes for experimental trabeculectomy in rabbits.

Postoperative Use of Cyclosporine, Prednisolone or a Cyclosporine/Prednisolone Combination to Treat Inflammation of the Conjunctiva Following Trabeculectomy in Rabbits

Objectives: The objective of this investigation was to compare different topical treatment protocols for controlling inflammation in rabbits during the postoperative period following trabeculectomy. Methods: Thirty rabbits had their right eyes treated with a daily eye drop of 0.03% bimatoprost for 30 days. All rabbits then underwent a trabeculectomy procedure and were divided into three groups (G1, G2 and G3). Rabbits from G1 received prednisolone acetate 1.0% four times a day, G2 received cyclosporine 0.05% twice a day and G3 Research Article Russ et al.; OR, Article no. OR.2013.001 75 received both prednisolone acetate 1.0% four times a day and cyclosporine 0.05% twice a day. Seven days after the surgery all rabbits were euthanized and enucleated. Histomorphometry was performed in HE-stained sections to evaluate epithelial thickness, blood vessel diameter and vascular area. Immunohistochemical staining using monoclonal antibodies against smooth muscle actin, factor VIII and IL-6 was performed to assessfibrosis, neovascularization and inflammatory cell infiltration, respectively. Results: In group G3 there was a reduction in the thickness and diameter of the conjunctival epithelium and the diameter and number of blood vessels, and less inflammatory infiltrate and fibrosis. Conclusion: This study suggests that a combination of prednisolone and cyclosporine is more effective than either of these drugs used alone to control postoperative conjunctival inflammation following trabeculectomy in rabbits.

Effect of Qingguangan on the expressions of MMP-2 and MMP-9 in filtering bleb after trabeculectomy in rabbits.

To explore the effect of Qingguangan on the expressions of MMP-2 and MMP-9 in filtering bleb scarring area after trabeculectomy in rabbit model. Thirty-two New Zealand rabbits were randomized into four groups: control group, experimental group, MMC group (ocular trabeculectomy in combination with MMC), and Qingguangan group. Trabeculectomy was performed on both eyes in each group except control group. Qingguangan group was mouth-fed with Qingguangan (solution). On postoperative day 14, the appearances of MMP-2 and MMP-9 on filtrating blebs were observed by immunohistochemistry. Statistical differences of the expressions of MMP-2 and MMP-9 were noted among groups on day 14 following surgery. Histology immunohistochemistry showed significant differences on the expressions of MMP-2 and MMP-9 between each group (P<0.05). Qingguangan can promote the expressions of MMP-2 and MMP-9.

Study of self-made freeze-dried bilayered fibrin-binding amniotic membrane in ocular trabeculectomy in rabbits.

To investigate the antifibrotic effect of freeze-dried bilayered fibrin-binding amniotic membrane on trabeculectomy in a rabbit model. Twenty-four Japanese white rabbits were randomized into three groups: the experimental group (ocular trabeculectomy in combination with freeze-dried bilayered fibrin-binding amniotic membrane transplantation), the control group (ocular trabeculectomy in combination with natural bilayered fibrin-binding amniotic membrane) and the blank group (single trabeculectomy). Clinical observation, hematoxylin-eosin staining, Massion staining, real-time PCR and immunohistochemistry for α-SMA were performed on days 7, 14, 21 and 30 following surgery. Statistical differences were noted in survival analysis and intraocular pressure (IOP) among groups on days 7, 14, 21 and 30 following surgery. Histology, immunohistochemistry and real-time PCR further demonstrated that trabeculectomy in combination with freeze-dried bilayered fibrin-binding amniotic membrane resulted in good wound healing and no scar formation. Self-made freeze-dried bilayered fibrin-binding amniotic membrane may inhibit the formation of scarring in glaucoma after trabeculectomy.

Anti-scar effect of bevacizumab by multiple-time and high-dose subconjunctival administration following trabeculectomy in rabbits

Background Bevacizumab is primarily aimed at pathologic angiogenesis for off-label uses such as the treatment of ocular neovascular disorders.However,as a new anti-fibrotic and anti-angiogenic agent following trabeculectomy,the safety and efficacy of bevacizumab by multiple-time and high-dose subconjunctival injection are still under study.Objective This study was to assess the safety and efficacy of bevacizumab after multiple-time and high-dose subconjunctival injections.Methods Regular trabeculectomy filtration surgery was performed on both eyes of 18 clean New Zealand White rabbits 0.1ml of bevacizumab(25g/L) was subconjunctivally injected intraoperatively and 3,5,7 days postoperatively in the left eyes of rabbits,and no any intervene in the right eyes were as normal controls.Bleb morphology was examined every 2 days and graded based on Moorefield's criteria and compared between the bevacizumab-treated eyes and normal saline(NS) eyes.The animals were sacrificed at 10,20 and 30 days after surgery respectively.The histopathological changes of the blebs were detected by hematoxylin and eosin stain to evaluate the cellular element around the bleb,and Masson stain was used to assess the degree of fibroblast proliferation.The degree of vascularity of bleb was identified by anti-vWf stain.Approval of this protocol was obtained and permitted from People's Hospital Institutional Animal Care and Use Committee of Peking University.The use of experimental animals complied with the Regulation for the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission.Results Compared to the NS-treated eyes,bevacizumab-treated eyes showed the larger and more diffusely elevated blebs with the significant difference(2.48±0.22cm2 versus 1.73±0.27cm2,t=5.194,P＜0.05).The survival time of the filtration bleb in bevacizumab panel was longer in bevacizumab-treated eyes compared to control eyes,showing a significantly difference between them(21.0±1.56 days versus 12.5±1.97 days,t=3.830,P=0.005).Histological and immunohistochemical analysis confirmed that bleb and adjacent conjunctiva vascularity(A value) was significantly less in bevacizumab-treated eyes than that in control eyes at 20 days after surgery with the difference value 14320.7±4134.9(t=12.275,P＜0.05),and fibroblast deposition value was evidently diminished after bevacizumab treatment at 30 days following surgery in comparison with control eyes with the mean difference 0.27±0.03(t=15.980,P＜0.05＝.Conclusion Repeated subconjunctival injection of bevacizumab can effectively prolong the survival time of bleb in a rabbit model of trabeculectomy and limit the degree and area of vascularization in 30 days following surgery.Bevacizumab inhibit fibroblast-meditated tissue formation significantly in the later phase of vascularization after trabeculectomy. Key words: Trabeculectomy; Bleb; Bevacizumab; Fibrosis; Vascularization; Subconjunctival injection

Effect of Doxycycline on Postoperative Scarring After Trabeculectomy in an Experimental Rabbit Model

To investigate effectiveness of doxycycline after trabeculectomy in rabbits by evaluating bleb appearance, intraocular pressure, and levels of matrix metalloproteinase-1, -2, -3, and -9 and tissue inhibitors of metalloproteinase (TIMP)-1 and -2 in the subconjunctival (sc) area. Twenty-nine New Zealand White rabbits were assigned into 1 of 6 groups as follows: topical doxycycline (0.1%), postoperative sc injection of doxycycline (100 mg/2 mL), and intraoperative mitomycin-C (MMC) (0.2 mg/mL) and their respective control groups. There was significant difference between intraocular pressure in the case groups, but there was no significant difference in topical doxycycline and MMC groups during the follow up. In the topical doxycycline group, levels of TIMP-1 and perifericTIMP-1 were higher and levels of perifericMMP-2 and inflammation were lower than their controls. In the sc doxycycline group, peripheral inflammation was higher than in the corresponding control. Only peripheral inflammation was significantly different between case groups, with the highest level in sc and the lowest level in MMC groups. Further, topical doxycycline group showed no significant difference in bleb appearance or peripheral inflammation compared with MMC group. Conjunctival burn and corneal vascularization were detected only in the sc doxycycline group. Topical doxycycline is more effective than sc doxycycline but is similar to MMC, and it can be an alternative to MMC in trabeculectomy in rabbits.

The influence of He-Ne laser on scar formation after trabeculectomy in rabbits.

To investigate the influence of He-Ne lasers on scar formation in the filtration canal after trabeculectomy in a rabbit model, as well as to explore the mechanisms for preventing scar formation when using He-Ne lasers in vivo. Experiment 1: Four groups were established (four eyes in each group). In 12 eyes, the upper nasal limbus area next to the upper rectus muscle received 10 minutes of He-Ne laser irradiation (100, 150, 200mW/cm(2); 60, 90, 120J/cm(2)) every day for three days. Four eyes served as controls. Twenty-four hours after the final irradiation, the rabbits were sacrificed and the irradiated tissue was excised, fixed with paraformaldehyde and tested for proliferating cell nuclear antigen (PCNA), connective tissue growth factor (CTGF) and apoptosis (TUNEL). Experiment 2: Forty-two rabbits were randomly divided into two groups and standard trabeculectomy was performed in the right eyes either after 200mW/cm(2) He-Ne laser irradiation or not in the filtration area. The expression of PCNA and CTGF, apoptosis and collagen density in the filtration area were tested on the 7(th), 14(th) and 28(th) day after surgery. Experiment 1: There were no more PCNA and CTGF positive cells in the He-Ne irradiation group than in the control group. No apoptotic cells were found in either group. Experiment 2: The expression of PCNA and CTGF was lower in the He-Ne irradiation group than in the control group on the 7(th) and 14(th) day after trabeculectomy surgery (P<0.05); no apoptotic cells were detected in either group. Collagen density was significantly lower in the He-Ne irradiation group than in the control group on the 14(th) and 28(th) day after surgery (P<0.05). Pretreating the filtration area with 200mW/cm(2) (120J/cm(2)) of He-Ne laser irradiation may be helpful in preventing scar formation after trabeculectomy, possibly due to the downregulation of the expression of PCNA, CTGF and collagen synthesis in fibroblasts.

A Comparative Study of the Effects of Ab Externo Superpulse Carbon Dioxide Laser-Assisted Trabeculectomy with Conventional Trabeculectomy in Rabbits

The aim of this investigation was to evaluate the efficacy of reduction in intraocular pressure (IOP) and complications in ab externo superpulse carbon dioxide laser-assisted trabeculectomy. Reduction of IOP remains the immediate goal of glaucoma treatment. Although trabeculectomy has been considered the gold standard for the surgical treatment of glaucoma, many complications are associated with this procedure. Laser surgery has been studied as an alternative way to control IOP in glaucoma. Sixty adult albino rabbits were enrolled in this study. The animals underwent one unilateral surgery of either trabeculectomy or ab externo superpulse carbon dioxide laser-assisted trabeculectomy and were divided into two subgroups, control or experimental. Follow-up examinations included ocular anterior segments, filtration blebs and IOP. Five eyes in each group were analyzed histologically one month postoperatively. Anterior chamber hyphema in the laser group was milder than that in the surgery group, and disappeared on the third day. In the surgery group, it disappeared by the end of the first month. Filtration blebs in the laser group formed earlier than in the surgery group. Comparing the laser group and the surgery group, IOP values in the laser group were more stable. Histological examination showed that the sclera tract was blocked by scar tissue, inflammation had infiltrated, and the anterior chamber angle had adhered in the surgery group. Ab externo superpulse carbon dioxide laser-assisted trabeculectomy was suggested as a feasible technique to control IOP with the advantages of more steady IOP reduction and fewer complications.

The antiscarring effects of chitosan film on trabeculectomy in rabbits

目的 几丁糖制成膜状对兔实验性小梁切除术滤过泡作用.方法 兔30只,双眼均行常规小梁切除术,每只兔随机选取1只眼为实验眼,植入几丁糖膜,另1只眼为对照眼,行常规小梁切除术不植入几丁糖膜.术后观察眼压,成纤维细胞计数,Kaplan-Meier分析法统计术后滤过泡情况.结果 (1)眼压:实验组术后1、2、4周眼压与术前相比差异有统计学意义,第5周开始眼压与术前相比差异无统计学意义.对照组术后1周与术前相比差异有统计学意义,第2周开始眼压与术前相比差异无统计学意义.术后1～4周,6周,8周,12周实验驵与对照组眼压相比差异有统计学意义,实验组低于对照组,第5周差异无统计学意义.(2)实验组滤过泡存留时间与对照组相比差异有统计学意义.(3)成纤维细胞计数:1、2、6、12周实验组与对照组差异有统计学意义(t=-5.541,-5.713,-5.499,-3.063,P<0.05),3周差异无统计学意义.(4)光镜下实验组1～3周均可见滤过道通畅,几丁糖膜呈均质状,6周滤过道部分阻塞,12周时闭合.对照组第3周开始滤过道消失.结论 兔小梁切除术后应用几丁糖膜能抑制成纤维细胞生长,降低眼压,延长滤过泡存留时间。

Expression of connective tissue growth factor after trabeculectomy in rabbits

To investigate the role of connective tissue growth factor (CTGF) after trabeculectomy associated with wound healing and to identify the role of CTGF in this process. It was a experimental study. Forty-nine rabbits were used and divided into 5 groups: normal eyes without trabeculectomy group (group A), ocular hypertension (OHT) model without trabeculectomy group (group B), OHT model with trabeculectomy group (group C), normal eyes with trabeculectomy group (group D) and normal eyes with sham operation group (group E). Group A and B were as control. CTGF mRNA was detected by RT-PCR using blebs and tissues harvested at day 2, 5, 7, and 14. Three replicates of three blebs per time point in the right eyes were collected. The expression of CTGF protein was detected by immunohistochemistry and inflammatory histopathology was inspected by HE staining using the whole eyeball harvested in the left eyes. Compared to group A and B, the expression of CTGF was significantly increased at day 5 after surgery (F = 19.54, P < 0.05) in group C, D, and E. The expression of CTGF mRNA in group C is significantly higher than that in group D at day 2 and 5 (t = 2.300, 5.140, P < 0.05), while group D is significantly higher than that in group E at day 2, 5, 7, and 14 (t = -2.927, -6.424, -4.176, -4.997, P < 0.05). The expression of CTGF protein in group C is significantly higher than that in group D (t = -7.147, -10.955, -9.900, -6.385, P < 0.05), and group D is higher than that in group E (F = 68.33, P < 0.05) at day 2, 5, 7, and 14, respectively. Inflammatory reaction reached peak at day 5 after surgery in group C, D, and E showing an infiltration of neutrophil, monocytes, macrophages, and the proliferation of fibroblast. Overexpression of CTGF in the blebs after trabeculectomy demonstrates that CTGF may play an important role in the process of wound healing. Furthermore, ocular hypertension may be involved in the upregulation of CTGF expression.

The antifibrosis effects of cyclosporin A-loaded chitosan nanoparticle on filtering bleb in experimental trabeculectomy in rabbits

目的 研究自制的环孢素A壳聚糖纳米微粒对实验性兔小梁切除术后滤过道瘢痕化的预防作用.方法 48只健康大耳白兔随机分为4组,均行单眼小梁切除术.术毕球结膜下分别注射CS(CsA)-NP、环孢素A(CsA)、壳聚糖纳米微粒(CS-NP)各0.5mL,对照组结膜下注射平衡盐溶液(BSS)0.5mL.于术后1d,1、2、4、8、12周查眼压(IOP)、滤过泡、角膜、虹膜、前房、晶状体、视网膜.结果 术后8周内各组平均IOP与术前比较差异均有统计学意义(P＜0.05).术后第4周CS(CsA)-NP组与CsA组平均IOP差异有统计学意义(F=2.91,P＜0.05).4组功能性滤过泡的生存时间差异有统计学意义(χ2=15.51,P＜0.01).结论 CS(CsA)-NP能抑制滤过区成纤维细胞的增生,有助于功能性滤过泡的维持,有效控制术后IOP,与CsA相比疗效高、不良反应小。

Laser-grid trabeculectomy in rabbits: an experimental in-vivo study.

Laser-grid trabeculectomy (TE) is a modification of micro-TE designed to enhance the intra- and postoperative safety of filtering surgery by creating several small oval fistulas (max. diameter <200 microm) beneath a scleral flap without peripheral iridectomy. After dissecting the conjunctiva and a conventional scleral flap, 10 small perforating fistulas were created in five pigmented rabbits in the region of the gray-white border using an erbium:YAG laser with a beveled side-firing 200 microm endoprobe; conventional TE with iridectomy was performed in another five animals. Anterior chamber inspection and IOP measurements of both eyes were conducted on days 1, 4, and 14 after operation. After the last inspection eyes were saved for morphological analysis. Both procedures (laser-grid and conventional TE) led to a reduction of intraocular pressure in the treated eye compared to the control eye. Differences between the outcomes for the two procedures were not statistically significant. Morphology of the eyes treated by laser-grid TE revealed dense scarring of perforations around the center of the ligamenta pectinata and loose tissue refilling of the more peripheral openings. The functional outcome of laser-grid TE in rabbits was similar to that of conventional TE in the short term. Histological examination of microperforations in the area of the trabecular meshwork after 2 weeks indicated that tissue repair was less pronounced than in the more anterior perforations. This morphologic finding may be of importance for non-penetrating glaucoma surgery.

Wound modulation after trabeculectomy by different formulations of antimetabolites in rabbits.

A prospective, randomized study was performed to examine the effects of subconjunctival retention of 5-fluorouracil (5-FU) microparticles or 5-FU microparticles combined with mitomycin-C (MMC) on the success of trabeculectomy procedure in 32 New Zealand white rabbits. Drug-loaded microparticles were prepared using a biodegradable polymer, 50:50 ploy (D,L-lactide-co-glycolide) (50:50, PLG, MW 9000), by an oil-in-oil emulsification/solvent extraction technique. Each rabbit underwent trabeculectomy on both eyes, then one of the 5-FU and/or MMC preparations was placed at the site of the filtering surgery intraoperatively in the right eye, while the left eye was used as a control. The rabbits were randomly allocated to one of four treatment groups: group 1 rabbits received 5% 5-FU microparticles 10 mg; group 2 rabbits received 10% 5-FU microparticles 10 mg; group 3 rabbits received 10% 5-FU microparticles 5 mg and MMC 0.01 mg (5-FU/MMC); and group 4 rabbits received MMC 0.02 mg. Postoperatively, intraocularpressure (IOP), bleb survival, complications and IOP dynamics were compared during a follow-up period of 42 days. The results showed that IOPs were significantly lower in the eyes that received groups 3 and 4 treatments, while the eyes that received low concentrations of 5-FU microparticles resulted in no difference in IOPs as compared with those of controls. At 42 days, blebs were present in 100% of the eyes treated with 5-FU/MMC and MMC, but 0% of the eyes treated with 5-FU microparticles. The blebs in the eyes treated with MMC 0.02 mg were thinner, and significant complications (endophthalmitis, transient corneal opacification and neovascularization) occurred. In addition, the IOP dynamics study revealed that the eyes treated with 5-FU/MMC and MMC resulted in less IOP spikings after intravenous infusion of 0.9% NaCl solution. Our study suggested that the use of 5-FU microparticles in promoting the success of trabeculectomy in rabbits is dose-dependent, and its effect is less potent than a single intraoperative application of MMC.

Subconjunctival retention of C3F8 gas increased success rates of trabeculectomy in rabbits.

The effect of subconjunctival retention of perfluoropropane (C3F8) gas on rabbit trabeculectomy was evaluated in this study to determine if this maneuver would increase the success rate of the surgery. Sixteen New Zealand white rabbits underwent trabeculectomy in the right eyes and trabeculectomy with subconjunctival retention of 0.3 mL C3F8 gas in the left eyes were used as animal models. One week and six weeks after the operations, the intraocular pressure (IOP) dynamics were compared between the two eyes after intravenous infusion of 0.9% NaCl sterile solution. The results showed that the average retention time of C3F8 gas within the subconjunctival space in the rabbits was 9.5 +/- 2.3 days. There were four parameters available in comparing IOP dynamics: Time Needed to Reach Peak IOP (TNRPI); Ascending Slope (AS); Peak IOP (PI) and Time Needed to Return to the Original IOP (TNROI). It was noted that at the 7th day after the operations, the IOPs in both eyes of the rabbits were not significantly increased after intravenous infusion of 0.9% NaCl solution. At the 42nd day, after 0.9% NaCl intravenous infusion, the eyes that had undergone trabeculectomy and subconjunctival retention of C3F8 gas had less IOP spiking than eyes that had undergone trabeculectomy alone (TNRPI: 6.7 +/- 2.2 vs. 4.2 +/- 2.9, p = 0.01, AS: 0.5 +/- 0.3 vs. 2.8 +/- 2.7, p = 0.002, PI: 24.4 +/- 9.6 vs. 18.7 +/- 7.4, p = 0.07 and TNROI: 6.8 +/- 5.8 vs. 14.7 +/- 11, p = 0.02). Our study suggested that subconjunctival retention of C3F8 gas increased the success rate of trabeculectomy in rabbits in the short-term follow-up period.