Objective To detect the effects of plasmin combined with hyaluronidase or hexafluoride SF6 on inducing posterior vitreous detachment (PVD). Methods Eighteen young pigmented rabbits were randomly divided into group A, B, and C with 6 rabbits in each. All of the right eyes were the experimental eyes and the left ones was the control. The right eyes in group A, B, and C were injected with plasmin 1 U, plasmin 1 U and hyaluronidase 20 U, and plasmin 1 U and SF6 0.5 ml, respectively; while all of the left eyes underwent intra-vitreous injection with balanced salt solution 0.1 ml. The eyes were observed by indirect ophthalmoscopy, slit lamp examination, biomicroscopy, B-ultrasonography, and electroretinography (ERG) before and after injection respectively. At last, the retinal sections were examined by light microscopy, scanning and transmission electron microscopy. Results The results of scanning microscopy showed incomplete PVD in 2 (33.3%) experimental eyes in group A, and complete PVD in 4 (66.7%) experimental eyes in both group B and C, and the positive rate of PVD in both group B and C significantly differed from that in group A (Plt;0.05). The b-wave amplitudes of ERG in the three groups after injection didn’t differ much from that in the control group or before the injection（Pgt;0.05）. The results of transmission electron microscopy and light microscopy indicated unchanged retinal structure. Conclusions Compared with the application of only plasmin, plasmin combined with hyaluronidase or hexafluoride SF6 can induce complete PVD more efficiently and do no harm to the retina. (Chin J Ocul Fundus Dis, 2005, 21: 388-390)
High myopia (HM) is one of the main causes of vision loss. In recent years, optical coherence tomography and other techniques have shown a variety of vitreoretinal interface abnormalities (VRIA) in highly myopic eyes. Posterior vitreous detachment and paravascular abnormality are the relatively common manifestations of VRIA. Posterior vitreous detachment is classified in several different ways in HM eyes, the onset age of which is earlier in HM. Paravascular abnormality mainly includes paravascular microfold, paravascular cyst, paravascular lamellar hole, and paravascular retinoschisis. The former two are early-stage lesions, the latter two are advanced lesions. VRIA is closely related to many HM's fundus complications, such as myopic retinoschisis, macular hole, retinal detachment and so on. VRIA may develop into myopic retinoschisis, which in turn develop into full-thickness macular hole, and even retinal detachment. Therefore, the examination and judgment of VRIA in HM patients are of great significance for the early prevention and treatment of clinical retina diseases.
Integrins is a family of multi-functional cell-adhesion molecules, heterodimeric receptors that connect extracellular matrix to actin cytoskeleton in the cell cortex, thus regulating various physiological and pathological processes. Risuteganib (Luminate®) is a novel broad-spectrum integrin inhibitor. Based on multiple biological functions of anti-angiogenesis, vitreolysis, and neuroprotection, risuteganib is hopeful in treating several fundus diseases such as diabetic macular edema, vitreomacular traction, and non-exudative age-related macular degeneration. By far, risuteganib has successfully met the endpoints for three phase 2 studies and is preparing to enter the phase 3 of diabetic macular edema clinical trials. Overall the risuteganib is safe with no serious ocular or systemic adverse events. Given the unique mechanism of action and longer duration of efficacy, intravitreal injection of risuteganib has the potential to serve as a primary therapy, or adjunctive therapy to anti-VEGF agents.
Objective To observe the safety and efficacy of posterior vitreous detachment (PVD) induced by combined intravetreal injection of lysineplasminogen and reteplase in rabbits.Methods Fifteen healthy New Zealand rabbits were divided into three groups with five rabbits in each. Take the right eyes as experimental eyes，while the left eyes as the control. The experimental eyes of three groups received combined intravetreal injection of 1250 mu;g/ml lysineplasminogen at 0.1 ml dose and 104U，3times;104U，105U reteplase at 0.05 ml dose recpectively, while the control eyes were injected intravetreally with 0.15 ml balanced salt solution. The conjunctiva, anterior chamber, lens, vitreous body, and retina were examined by slit lamp microscope and +120D preset lens. The retinal function was examined by electroretinogram (ERG).Results All the experimental eyes had PVD. The results of optical microscope showed that no change in retinal structure was found in the control group and 104 U reteplase group, clear retinal hierarchical but decreased ganglion cells and kernel layer cells were found in 3times;104 U reteplase group, only retinal pigment epithelium layer but no normal retinal structure was observed in 105U reteplase group. The results of ERG showed that compared the maximum mixed reaction of a and b wave amplitude in control group and reteplase group respectively, the difference was not statistically siginificant between 104U reteplase group and control group(a wave：t=0.881，-1.773，0.809；b-wave：t=-0.223，-0.441，1.400；P＞0.05),the differences were statistically siginificant between 3times;104 U(a wave：t=-3.20，b-wave：t=-4.182，-4.103),105 U reteplase group(a wave：t=-0.737，b wave：t=-15.150，6.597)and control group(P＜0.05). The control eyes didnprime;t had PVD.Conclusion Combined intravetreal injection of lysine-plasminogen and reteplase can induce complete PVD, and no damage to the retinal structure in rabbits.
Objective To investigate the effects of intravitreal injection of matrix metalloproteinase-3 (MMP-3) on the vitreoretinal adhesion and the vitreous gelatin. Methods Twenty-four pigmented rabbits were randomly divided into 3 experimental groups（group A, B, and C）and one control group with 6 rabbits (12 eyes) in each. Different concentrations of 0.1 ml MMP-3 (5,10, 20 ng in group A, B, and C, respectively) and equivalent dose of balanced salt solution were intravitreally injected to the rabbits, respectively. Clinical examinations (such as gross observation, slit-lamp biomicroscopy, indirect fundus ophthalmoscopy ), electroretinography (ERG) and fundus fluorecein angiography (FFA) were taken before and after injection. Results One week after injection, posterior vitreous detachment (PVD) and focal vitreous liquefaction were recognized clinically for the first time in 1 eye in group B. By the end of this study, clinically detected PVD developed in 1 eye in group A, 3 eyes in group B, but the synchisis developed slowly, and no liquefaction or PVD occurred in control group. As for the histological examination, partial PVD was observed in 1 eye in group A and 3 eyes in group B 60 minutes after injection. All of the eyes in group A and B showed partial PVD 1 week after injection, and the area of PVD enlarged in contrast with before. Complete PVD were recognized in 1 eye in group A and 3 eyes in group B 15 weeks after injection, and the cleavage was narrow and limited. In group C, inflammatory cell infiltration in the inner layer of retina, destruction of retinal structure, and fluorescein leakage at late phase was found in the early period after injection. Conclusions MMP-3 is effective in disrupting the adhesion of the posterior hyaloid to the inner limiting membrane leading to PVD, and helpful to some extent in producing vitreous liquefaction. The dose of 10 ng MMP-3 is safe and effective for the rabbits eyes, which may be used as an promising assistant of vitreous surgery. (Chin J Ocul Fundus Dis，2004，20：67-132)