The effect of gene-transferred TIMP-2 on the biology and scleral morphology in form deprivation myopia in guinea pigs

Abstract

Objective To observe axial length,refraction and morphology in form-deprivation myopia (FDM) with gene-transferred tissue inhibitors of metalloproteinase (TIMP-2) in guinea pigs.Methods Sixty four-week-old guinea pigs in this experimental study were randomly divided into 4 groups:TIMP-2 group,empty plasmid group,saline group and control group.A FDM model was established in the right eye by using a translucent plastic occluder.The left eye of the TIMP-2 group was considered as the self-control group.Gene-transferred liposome,empty plasmidtransferred liposome and saline were injected in the first 3 groups,respectively,on the 15th day of deprivation.Refraction,axial length and the scleral structure were observed on 2,7 aud 14 days after injection.Data were analyzed using two-way analysis of variance.Results On 2,7 and 14 days after injection,the average amounts of myopia in the TIMP-2 group were-0.4±0.5 D,0.9±0.6 D and 1.2±0.6 D.The differences for the day 14 were statistically significant compared to the other 3 groups (q=5.78,5.34,6.07,P＜0.05).Compared with the control group,the differences of day 2,7,14 were statistrcallv significant (q=13.09,9.72,6.93,P＜0.05).On 2,7 and 14 days after injection,the axial lengths of the experimental group were 7.78±0.04 mm,7.69±0.03 mm and 7.65±0.03 mm.The differences on days 7 and 14 were statistically significant compared to the control groups (q7=5.51,4.43,4.82,q14=5.36,4.78,5.16; P＜0.05).The collagen fibrillar diameters of the sclera in the posterior segment of FDM eyes were found to he distinctly bigger and the space between the fibers was smaller than that of the control eyes.The average diameters of the fiber in the TIMP-2 group were 49.7±6.8 nm,71.3±6.0 nm and 97.8±10.4 nm,respectively,2,7 and 14 days after injection.The differences on day 7 and 14 were statistically significant compared to the the other 3 groups (q7=30.70,12.30,12.20,q14=21.80,21.50,21.20; P＜0.05).Compared with the control group,the differences of day 2 were statistically significant (q=14.40,P＜0.05).Conclusion The ectogenic gene of TIMP-2 has an inhibitory effect on the changes in the biology and morphology in form-deprivation myopia of guinea pigs. Key words: Form-deprivation myopia; Tissue inhibitors of metalloproteinase-2; Gene transfection; Sclera ; Guinea pig