Dynamic changes of ocular biometric parameters:a modified form-deprivation myopia model of young guinea pigs

AIM: To evaluate the dynamic ocular biometric changes of a modified form-deprivation myopia model in young guinea pigs. METHODS: The animals were randomly assigned to two groups: the monocularly deprived facemask group (MDF, with all the right eyes covered, n=24) and the normal control group(free of facemask, n=24). Each group was then equally divided into four subgroups which were followed up for 2, 4, 6 and 8 weeks, respectively. Parameters measured from every eye included refraction, corneal curvature, axial length and the dry weight of sclera at the posterior pole. RESULTS: All the facemasks remained in place during the follow-up. The covered eyes developed myopia with the vitreous chamber lengthening and the dry weight of posterior sclera reduced at each time point compared with the contralateral uncovered (P<0.05 at all time points). The changes had a linear correlation with the deprivation time (P<0.05). There were no significant differences in all the parameters between the uncovered eyes of MDF group and the normal control group (P>0.05 at all time points). CONCLUSION: Monocular form deprivation with the facemask is highly effective and non-invasive in inducing axial myopia in guinea pigs. The axial myopia is mainly caused by the increased vitreous chamber length and the weakened posterior sclera rigidity. The form-deprivation eye didn't interfere with the natural development of the contralateral eye.

Refractive Changes in Chicks with Form-deprivation Myopia

Purpose: To study the refractive changes of form deprivation of myopia. Methods: Haisaik chickens were used to establish the animal models of myopia. Monocular eyelids were sutured for form deprivation on the 5th day after chickens birth. The chickens were examined by optometer and the anteroposterior axis, transverse and vertical diameters were measured by verniermicrometer. Results: Form deprivation leads to myopic refractive abnormality (P【0. 001). The ocular anteroposterior axis (P【0. 005), transverse and vertical diameters lengthen (P【0. 05).Conclusion: Form deprivation is the main cause of the development of myopia. Eye Science 1996; 12:138-139.

Comparison of form-deprived myopia and lens-induced myopia in guinea pigs

AIM:To study the efficacy difference between formdeprived myopia(FDM)and lens-induced myopia(LIM),the degree of myopia,axial length and pathological changes of the posterior sclera from guinea pigs were evaluated.METHODS:Four-week pigmented guinea pigs were randomly assigned into 3 groups,including normal control(n=6),FDM group with monocular cover(n=11)and LIM group with monocular-7D lens treatment(n=11).FDM group was form-deprived while LIM group was lens-induced for 14d.Refractive error and axial length were measured prior to and post treatment,respectively.Morphological changes of sclera were examined using both light and electronic microscopes.RESULTS:After 14d treatment,refractive errors for FDM group and LIM group were-3.05±0.71D and-2.12±1.29D,respectively,which were significantly more myopic than that of normal controls and fellow control eyes(P【0.01).As for axial length,it was 7.93±0.03 mm for FDM group and 7.89±0.06 mm for LIM group,which were significantly longer than both normal and fellow controls(P【0.01).With respect to both refractory error and axial length,the differences between FDM group and LIM group were not significant(P】0.05).Under light microscope,both FDM group and LIM group showed thinned sclera,disarrangement of fibrosis and enlargeddisassociation between fibers.Consistently,ultrastructural examination showed degenerated fibroblasts and thinned fibers in posterior sclera.CONCLUSION:Following two weeks of myopia induction in guinea pigs,with regard to the degree of myopia,axial length and pathological alterations,there was no significant difference between FDM and LIM models.Therefore,FDM and LIM are equally effective and useful as a model of experimental myopia and guinea pigs are ideal animals for induction of experimental myopia because their high sensitivity to both formdeprivation and lens-induction.

Effects of Cyclopentolate on Form Deprivation Myopia in Guinea Pigs

Purpose: To investigate the effects of intravitreal injection of cyclopentolate on form deprivation myopia in guinea pigs. Methods: Thirty-five guinea pigs at age of 3 weeks were randomly divided into 5 groups (n = 7 for each group): deprived, deprived plus saline, deprived plus cyclopentolate, normal control, and cyclopentolate group. Form deprivation was only performed in right eyes with translucent membranes for 4 weeks. Physiological saline and cyclopentolate were intravitreally injected into deprived eyes at four-day intervals. All the left eyes remained untreated as group control. Refraction was measured by retinoscopy after cycloplegia. The axial dimensions were measured by A-scan ultrasound. Subsequently, retinal histology was observed by light microscopy. Results: After 4 weeks of treatment, intravitreal injection of cyclopentolate significantly reduced the degree of myopia in the deprived eyes (from -3.92 D to -0.86 D, P < 0.001), and retarded the increase of vitreous chamber depth (from 3.83 ± 0.06 mm to 3.70 ± 0.05 mm, P < 0.001) and axial length (from 8.42 ± 0.04 mm to 8.30 ± 0.05 mm, P < 0.001) in the deprived eyes. Histological ex-amination revealed no evidence of retinal damage of eyes injected with physiological saline or cy-clopentolate compared with normal control eyes. Conclusions: Intravitreal administration of cy-clopentolate reduces axial elongation of the deprived eyes in guinea pigs. Further investigations are required to identify the optimal dose.

Mechanism of the DL-alpha-aminoadipic acid inhibitory effect on form-deprived myopia in guinea pig

AIM:To investigate the effect of intravitreal injection of DL-alpha-aminoadipic acid (DL-α-AAA) on ocular refractive state and retinal dopamine, transforming growth factor-β2 (TGFβ2 ), vasoactive intestinal polypeptide (VIP) in guinea pig form-deprived myopia. METHODS:Four-week-old pigmented guinea pigs were randomly assigned to 4 groups:normal control, deprivation, deprivation plus DL-α-AAA, deprivation plus saline. Form deprivation was induced with the self-made translucent eye shields, and lasted for 14 days. 8μg DL-α-AAA was injected into the vitreous chamber of deprived eyes. The corneal radius of curvature, refraction and axial length were measured. Retinal dopamine content was evaluated by the high-performance liquid chromatography with electrochemical detection, and TGFβ2 and VIP protein were detected by Western blotting. RESULTS:Fourteen days of eye occlusion caused the axial length to elongate and become myopic in the form-deprived eyes, with the decrease of retinal dopamine and the increase of TGFβ 2 and vasoactive intestinal polypeptide (VIP) protein. Intravitreal injection of DL-α-AAA could inhibit the myopic shift from (-3.65±1.06)D to (-1.48 ±0.63)D, P 【0.01 due to goggles occluding and cause the decrease of retinal TGFβ2 protein in the deprived eyes. However, intravitreal injection of DL-α-AAA had no significant effect on retinal dopamine and VIP protein in deprived eyes. Retinal TGFβ2 protein correlated highly with the ocular refraction (y =-3.34 + 0.31/x , F =74.75, P 【0.001) and axial length (y =8.39-0.02/ x , F =48.32, P 【0.001) in different treatment groups. ·CONCLUSION:Intravitreal injection of DL-α-AAA is effectively able to suppress the development of form deprivation myopia, which may be associated with retinalTGFβ2 protein in guinea pigs.

养血补肾方对形觉剥夺性近视豚鼠巩膜重塑及TGF-β2的作用研究

目的观察养血补肾方对形觉剥夺性近视(FDM)豚鼠巩膜胶原及转化生长因子-β2(TGF-β2)表达的影响。方法40只三色豚鼠右眼以半透明塑料眼罩行遮盖作为模型眼,左眼作为对照眼,建立FDM模型,分别于干预前1 d和干预60 d后检测双眼屈光度、眼轴变化。将造模成功的豚鼠随机分为模型组(MG)和养血补肾方组(YXBS),各20只,YXBS组灌胃养血补肾方,MG组灌胃等体积0.9%氯化钠注射液。连续给药15 d后,苏木精—伊红染色(HE)法观察豚鼠巩膜形态,免疫组织化学染色检测巩膜TGF-β2表达。结果(1)屈光度与眼轴:造模后MG组豚鼠模型眼屈光度较造模前降低(t=15.960,P=0.000),且低于造模后的对照眼(t=14.962,P=0.000),差异有统计学意义。造模后MG组豚鼠双眼眼轴均较造模前延长(t模型眼=21.274,t对照眼=15.844,均P=0.000),且模型眼眼轴长于对照眼(t=5.998,P=0.000),差异均有统计学意义。(2)巩膜形态:MG组豚鼠模型眼巩膜厚度明显缩小,巩膜胶原稀疏,纤维间隙扩大;YXBS组豚鼠模型眼巩膜胶原排列较紧密,纤维间隙较小。(3)巩膜TGF-β2:2组对照眼的TGF-β2表达水平比较,差异无统计学意义(P>0.05);与对照眼比较,2组模型眼巩膜TGF-β2表达水平均降低(tYXBS=4.538,tMG=6.981,均P=0.000),且YXBS组模型眼TGF-β2表达水平高于MG组模型眼(t=2.154,P=0.049),差异均有统计学意义。结论养血补肾方能上调FDM豚鼠巩膜组织中TGF-β2的表达,调节巩膜重塑,延缓巩膜变薄,这可能是其调控近视进展的机制之一。

血管内皮生长因子-A_(165)对形觉剥夺性近视豚鼠巩膜重塑的影响

目的:探讨玻璃体腔内注射血管内皮生长因子-A_(165)(VEGF-A_(165))对形觉剥夺性近视(FDM)豚鼠巩膜重塑的影响。方法:健康3周龄三色豚鼠120只随机分为6组,每组20只,其中空白组不做任何干预,FDM组仅建立FDM模型,PBS组建立FDM模型前玻璃体腔内注射PBS缓冲液2.5μL,1ng组、5ng组、10ng组建立FDM模型前玻璃体腔内分别注射VEGF-A_(165)1、5、10ng。用半透明气球遮盖豚鼠右眼14d建立FDM模型,造模前后测量豚鼠右眼屈光度和眼轴长度,造模14d后采用高效液相色谱法检测视网膜中多巴胺(DA)含量,用RT-PCR、Western blot法检测巩膜中基质金属蛋白酶-2(MMP-2)、基质金属蛋白酶抑制剂-2(TIMP-2)、转化生长因子(TGF)-β1、TGF-β2、α-平滑肌肌动蛋白(α-SMA)的mRNA和蛋白表达情况。结果:造模前,各组豚鼠右眼屈光度和眼轴长度均无显著差异(P>0.05)。造模14d后,与空白组相比,FDM组豚鼠右眼近视度数升高,眼轴增长,视网膜中DA含量减少,巩膜中MMP-2、TGF-β2、α-SMA表达量均增加,TIMP-2、TGF-β1表达量均减少(P<0.01);与FDM组相比,1ng组、5ng组、10ng组豚鼠右眼近视度数均降低,眼轴增长趋势均减缓,视网膜中DA含量均增加,巩膜中MMP-2、TGF-β2、α-SMA表达量均减少,TIMP-2、TGF-β1表达量均增加(P<0.01),且随着玻璃体腔注射VEGF-A_(165)浓度的升高,豚鼠右眼近视度数逐渐升高,眼轴逐渐延长,视网膜中DA含量逐渐减少,巩膜中MMP-2、TGF-β2、α-SMA表达量均逐渐增加,TIMP-2、TGF-β1表达量均逐渐减少。结论:玻璃体腔内注射VEGF-A_(165)可以增加FDM豚鼠视网膜中DA含量,影响巩膜中MMP-2、TIMP-2、TGF-β1、TGF-β2、α-SMA的表达,抑制巩膜重塑,其中1ng VEGF-A_(165)效果最明显。

血管内皮生长因子-A_(165)对形觉剥夺性近视豚鼠视网膜中多巴胺水平的影响

目的研究玻璃体内注射血管内皮生长因子-A_(165)(VEGF-A_(165))对形觉剥夺性近视(FDM)豚鼠视网膜中多巴胺(DA)水平的影响。方法选取健康3周龄三色豚鼠90只,随机分为6组,分别为空白组、FDM组、PBS组、10 ng组、5 ng组、1 ng组,每组15只。空白组豚鼠双眼不做任何处理,其他组豚鼠用半透明乳胶气球套头连续遮盖右眼14 d建立FDM模型,左眼不做处理。PBS组、10 ng组、5 ng组、1 ng组豚鼠于遮盖前右眼玻璃体内分别注射PBS缓冲液和10 ng、5 ng、1 ng VEGF-A_(165)。在造模前1 d和造模后14 d测量豚鼠右眼屈光度和眼轴长度。造模后14 d,采用免疫荧光法检测各组豚鼠视网膜中酪氨酸羟化酶(TH)阳性细胞数,高效液相色谱法测定DA、DOPAC的含量及DA代谢率,HE染色观察视网膜中血管内皮细胞核数。结果造模前,6组豚鼠右眼屈光度和眼轴长度差异均无统计学意义(均为P>0.05)。造模后14 d,与空白组相比,FDM组豚鼠近视度数升高,眼轴长度增加,TH阳性细胞数降低,DA、DOPAC含量降低,差异均有统计学意义(均为P<0.05);与FDM组相比,10 ng组、5 ng组、1 ng组豚鼠右眼近视度数均降低,眼轴长度均变短,TH阳性细胞数均增加,DA、DOPAC含量均增多,血管内皮细胞核数均增加,其中5 ng组豚鼠近视度数及眼轴长度均低于10 ng组,TH阳性细胞数及DA、DOPAC含量均高于10 ng组,1 ng组豚鼠近视度数及眼轴长度均低于5 ng组,TH阳性细胞数及DA、DOPAC含量均高于5 ng组,差异均有统计学意义(均为P<0.05);10 ng组豚鼠视网膜血管内皮细胞核数最多,5 ng组次之,1 ng组较少,但与空白组相比差异均有统计学意义(均为P<0.05);6组豚鼠间视网膜DA代谢率差异无统计学意义(P=0.574)。结论玻璃体内注射VEGF-A_(165)可以使FDM豚鼠视网膜中DA含量升高,从而抑制豚鼠近视的发展。

针刺对形觉剥夺性近视豚鼠巩膜形态及组织中HIF-1α、SOD、MDA水平的影响

目的 探究针刺对形觉剥夺性近视(FDM)豚鼠巩膜组织形态特点及巩膜组织中缺氧诱导因子1α(HIF-1α)、超氧化物歧化酶(SOD)、丙二醛(MDA)水平的影响。方法 选取普通级3周龄健康三色豚鼠72只,随机分为空白组、模型组和针刺组(各24只)。用半透明气球作为眼罩分别固定于模型组和针刺组豚鼠右眼及头面部建立FDM模型,左眼充分暴露作自身对照;针刺组在豚鼠模型建立当天起,于每日相同时间对豚鼠进行针刺和电针干预治疗,空白组豚鼠不做任何干预。记录每组豚鼠造模前、造模后2周及4周的眼轴长度和屈光度。造模后4周处死豚鼠,光学显微镜下观察巩膜形态变化,Western blot检测各组豚鼠巩膜中HIF-1α蛋白表达,比色法测定各组豚鼠巩膜中SOD活力和MDA含量。结果 造模后2周和4周,与空白组比较,模型组及针刺组豚鼠遮盖眼近视屈光度及眼轴长度均明显增加(均为P<0.05);与模型组比较,针刺组豚鼠遮盖眼近视屈光度减小,眼轴增长明显减缓(均为P<0.05)。造模后4周,与空白组比较,模型组豚鼠巩膜厚度明显变薄,胶原纤维分布稀疏,有明显纤维空隙且排列不规则;与模型组相比,针刺组豚鼠巩膜层增厚,与胶原纤维分离程度较小且排列更加规则。造模后4周,与空白组相比,模型组豚鼠巩膜中HIF-1α蛋白表达显著升高(P<0.01);与模型组相比,针刺组豚鼠巩膜中HIF-1α蛋白表达显著降低(P<0.01)。造模后4周,与空白组相比,模型组豚鼠巩膜中SOD活性显著降低,MDA含量显著提高(均为P<0.01);与模型组相比,针刺组豚鼠巩膜中SOD活性显著升高,MDA含量显著降低(均为P<0.05)。结论 针刺治疗可通过调节FDM豚鼠巩膜中HIF-1α、SOD及MDA的表达,改善巩膜缺氧及抗氧化应激状态,延缓近视的发生发展。

“益阳坚阴”复方中药对形觉剥夺性近视豚鼠眼眼轴轴、MMP-2及COL-I表达的时效研究

目的 观察“益阳坚阴”复方中药对形觉剥夺性近视(FDM)豚鼠的眼轴、MMP-2及COL-I表达的时效研究。方法 选取3周龄雄性花豚鼠72只,随机分为空白对照组(A组)、模型组(B组)、中药干预组(C组);B组及C组豚鼠均缝合右眼;A组和B组每日予0.9%氯化钠注射液10 mL/kg灌胃,C组每日予10 mL/kg的“益阳坚阴”复方中药灌胃。连续干预2周及4周后取材,所有豚鼠干预前后行A超测量眼轴,干预后取材行Western-blot法检测豚鼠视网膜组织中基质金属蛋白酶-2(MMP-2)及巩膜组织中巩膜I型胶原(COL-I)的含量,对数据进行统计分析。结果 (1)眼轴:①干预2周后,3组干预前后比较,眼轴均有增长(Z_(A)=-5.504,Z_(B)=-7.491,Z_(C)=-7.382,均P=0.000)。3组间眼轴比较,差异有统计学意义(H=20.439,P=0.000)。与A组比较,B组豚鼠眼轴明显增长(Z=-3.941,P=0.000);而C组眼轴无明显增长(P>0.05)。与B组比较,C组眼轴较短(Z=-3.392,P=0.001)。②干预4周后,3组干预前后比较,眼轴均增长(Z_(A)=-6.819,Z_(B)=-8.466,Z_(C)=-8.853,均P=0.000)。3组间眼轴比较,差异有统计学意义(H=17.997,P=0.000)。与A组比较,B组及C组豚鼠干预后眼轴均有增长(Z_(B)=-3.449,P=0.001;Z_(C)=-3.881,P=0.000);与B组比较,C组眼轴差异无统计学意义(P>0.05)。(2)MMP-2、COL-I表达水平:①干预2周后,3组间MMP-2、COL-I蛋白表达水平比较,差异具有统计学意义(F_(MMP-2)=69.529,P=0.000;F_(COL-I)=23.753,P=0.001)。与A组比较,B、C组的MMP-2蛋白表达水平升高(t_(B)=-10.353,P=0.000;t_(c)=-3.733,P=0.020),B组的COL-I蛋白表达水平降低(t=8.155,P=0.001),而C组的COL-I蛋白表达水平比较差异无统计学意义(P>0.05);与B组比较,C组的MMP-2蛋白表达水平降低(t=7.860,P=0.001)、COL-I蛋白表达水平升高(t=-4.670,P=0.010),差异均有统计学意义。②干预4周后,3组间MMP-2、COL-I蛋白表达水平比较,差异具有统计学意义(F_(MMP-2)=143.191,P=0.000;F_(COL-I)=19.765,P=0.002)。与A组比较,B组及C组的MMP-2蛋白表达水平均升高(t_(B)=-19.549,P=0.000;t_(C)=-7.315,P=0.002),COL-I蛋白表达水平均降低(t_(B)=4.837,P=0.008;t_(C)=5.234,P=0.006);与B组比较,C组的MMP-2蛋白表达水平降低(t_(C)=8.483,P=0.001),差异有统计学意义;而COL-I蛋白表达水平,差异无统计学意义(P>0.05)。结论 “益阳坚阴”复方中药在干预2周后可以抑制FDM豚鼠眼轴的发展,推测可能与下调MMP-2的表达,减少COL-I胶原降解有关。

Intravitreal brimonidine inhibits formdeprivation myopia in guinea pigs

Background:The use of ocular hypotensive drugs has been reported to attenuate myopia progression.This study explores whether brimonidine can slow myopia progression in the guinea pig form-deprivation(FD)model.Methods:Three-week-old pigmented male guinea pigs(Cavia porcellus)underwent monocular FD and were treated with 3 different methods of brimonidine administration(eye drops,subconjunctival or intravitreal injections).Four different concentrations of brimonidine were tested for intravitreal injection(2μg/μL,4μg/μL,20μg/μL,40μg/μL).All treatments continued for a period of 21 days.Tonometry,retinoscopy,and A-scan ultrasonography were used to monitor intraocular pressure(IOP),refractive error and axial length(AL),respectively.On day 21,guinea pigs were sacrificed for RNA sequencing(RNA-seq)to screen for associated transcriptomic changes.Results:The myopia model was successfully established in FD animals(control eye vs.FD eye,respectively:refraction at day 20,0.97±0.18 D vs.−0.13±0.38 D,F=6.921,P=0.02;AL difference between day 0 and day 21,0.29±0.04mm vs.0.45±0.03 mm,F=11.655,P=0.004).Among the 3 different brimonidine administration methods,intravitreal injection was the most effective in slowing myopia progression,and 4μg/μL was the most effective among the four different concentrations of brimonidine intravitreal injection tested.The AL and the refraction of the brimonidine intravitreal injection group was significantly shorter or more hyperopic than those of other 2 groups.Fourμg/μL produced the smallest difference in AL and spherical equivalent difference values.FD treatment significantly increased the IOP.IOP was significantly lower at 1 day after intravitreal injections which was the lowest in FD eye of intravitreal injection of brimonidine.At day 21,gene expression analyses using RNA-seq showed upregulation of Col1a1 and Mmp2 expression levels by intravitreal brimonidine.Conclusions:Among the 3 different administration methods,intravitreal injection of brimonidine was the most effective in slowing myopia progression in the FD guinea pig model.Intravitreal brimonidine at 4μg/μL significantly reduced the development of FD myopia in guinea pigs.Expression levels of the Col1a1 and Mmp2 genes were significantly increased in the retinal tissues of the FD-Inj-Br group.

650nm半导体激光对形觉剥夺性近视豚鼠视网膜厚度的影响

目的比较不同照射时长650 nm半导体激光对形觉剥夺性近视(FDM)豚鼠视网膜厚度的影响。方法通过头套法建立豚鼠单眼形觉剥夺性近视模型,分为正常对照组(n=10)、单纯遮盖组(n=10)和遮盖+激光照射组(n=30),遮盖+激光照射组的豚鼠每天接受两次650 nm激光照射,根据不同照射时长又分为3 min组(n=10)、6 min组(n=10)和12 min组(n=10)。4周后通过带状光检影镜测量每组豚鼠的屈光度值,用光学相干断层扫描仪(OCT)测量每组豚鼠后极部视网膜厚度,分析比较各组间豚鼠眼球屈光度和视网膜厚度的差异。结果单纯遮盖组豚鼠屈光度较正常对照组有明显近视形成(P<0.05),各遮盖+激光照射组的豚鼠屈光度值均较单纯遮盖组减小,其中6 min和12 min激光组较3 min激光组的近视屈光度减少(P<0.05),但6 min激光组与12 min激光组豚鼠的近视屈光度无明显差异(P>0.05)。单纯遮盖组豚鼠后极部视网膜厚度较正常组明显变薄(P<0.05),各遮盖+激光照射组的豚鼠视网膜厚度均较单纯遮盖组视网膜厚度有所增加(P<0.05),6 min和12 min激光组均较3 min激光组豚鼠视网膜厚度增加(P<0.05),但6 min激光组与12 min激光组豚鼠的视网膜厚度无明显差异(P>0.05)。结论650 nm半导体激光可以控制豚鼠形觉剥夺性近视的发展,并改善其视网膜厚度变薄的趋势。

鸡形觉剥夺性近视眼后极部巩膜IGF-1R/IGF-2RmRNA的表达

目的:观察鸡形觉剥夺性近视眼后极部巩膜IGF-1R/IGF-2RmRNA表达水平的变化,探讨IGF-1R/IGF-2R在实验性近视眼发生机制中的信号转导作用。方法:孵化1d的白色来亨鸡36只,右眼为遮盖眼,左眼为自身对照眼;测量实验前、单眼遮盖1,2,3wk时遮盖眼和对照眼的屈光度和眼轴长度,并检测不同遮盖时间鸡眼后极部巩膜IGF-1R/IGF-2RmRNA的表达水平。结果:鸡眼后极部巩膜可检测到IGF-1R/IGF-2Rm-RNA的表达,随着眼球的生长发育其表达水平明显升高;随着遮盖时间的延长,IGF-1R/IGF-2RmR-NA在遮盖眼后极部巩膜的表达水平显著升高;遮盖眼后极部巩膜IGF-1RmRNA的表达水平自遮盖1wk起明显高于对照眼;IGF-2RmRNA表达水平则在对照眼与遮盖眼无显著差异。结论:形觉剥夺可能通过上调鸡眼后极部巩膜IGF-1RmRNA表达水平,IGF-1R通过结合IGF并启动下游信息转导途径,从而调控巩膜细胞的增殖和分化,导致近视的发生。

Caspase-3在形觉剥夺性近视眼视网膜中的表达意义

目的:研究鸡形觉剥夺性近视眼发展过程中视网膜caspase 3蛋白的变化及视网膜细胞的凋亡情况。方法:眼睑缝合法建立鸡的近视眼模型。按预定时间检影验光,游标卡尺测眼球外径,免疫组化检测视网膜中caspase 3蛋白的表达,色敏比色法定量分析caspase 3活性变化,末端脱氧核苷酸连接酶介导生物素化脱氧尿苷酸末端标记(TdT‐mediatedbiot in‐dUTP nick‐end labeling,TUNEL)技术及流式细胞术检测视网膜的凋亡细胞。结果:眼睑缝合12wk后,缝合眼屈光度加深、眼球外径增大,视网膜感光细胞内节及外丛状层caspase-3蛋白表达上调,色敏比色法测量的视网膜caspase-3活性明显高于对照眼。缝合眼视网膜内、外核层发现凋亡细胞,凋亡率明显高于对照眼。结论:鸡形觉剥夺性近视眼发展过程中,视网膜细胞出现明显凋亡,caspase-3参与凋亡的发生。

小鸡FDM后极部巩膜MMP-2活性表达的动态变化

目的:研究形觉剥夺对小鸡后极部巩膜基质金属蛋白酶2(MMP2)活性的影响以阐明小鸡形觉剥夺性近视眼(FDM)巩膜重塑的可能机制。方法:50只1d龄来亨雏鸡采用半透明塑料眼罩单眼遮盖制备FDM动物模型,按实验时间随机分为FDM4,7,14,21,30d5组,每组10只。对侧非遮盖眼作为自身对照。另外,每组随机选取10只同龄、非遮盖小鸡作为正常对照。于预定实验时间分别采用视网膜镜与A超检测实验眼屈光度与眼轴长度,采用明胶酶谱法检测各组小鸡后极部巩膜明胶酶活性变化。结果:各FDM组后极部巩膜MMP2活性增高,与自身对照、正常对照组比较差异有统计学意义(P<0.01);随着剥夺时间延长,其后极部巩膜MMP2活性水平逐渐升高,至21d达高峰,其后稍下降,但仍维持于较高水平,不同FDM组组间差异有统计学意义(P<0.01);小鸡FDM后极部巩膜MMP2活性动态变化与眼轴长度、屈光度变化呈高度一致;后极部巩膜MMP2活性与眼轴长度呈正相关(r=0.989,P<0.01),与屈光度呈负相关(r=-0.989,P<0.01)。结论:后极部巩膜MMP2活性特异性增高极可能为启动小鸡FDM巩膜细胞外基质(ECM)主动重塑的原因之一。

小鸡形觉剥夺性近视眼巩膜TIMP-2 mRNA表达的时间动态变化

目的 探讨小鸡形觉剥夺性近视眼(FDM)后极部巩膜基质金属蛋白酶2组织抑制剂(TIMP-2)mRNA表达水平的动态变化。方法 取1d龄来亨雏鸡以半透明眼罩分别遮盖右眼4、7、14、21、30d制备FDM动物模型,未遮盖眼为自身对照眼,并随机选取同数目同龄小鸡作为正常对照眼。实验前及预定实验时间进行视网膜检影验光和眼轴长度测量,摘除眼球,提取后极部巩膜总RNA,采用一步法逆转录-多聚酶链反应检测每组小鸡后极部巩膜TIMP-2 mRNA表达水平。结果 与正常组、自身对照组相比,FDM后极部巩膜TIMP-2 mRNA表达明显降低,组间差异非常显著(P<0.01)。随遮盖时间延长其表达降低,7～21d降低最明显,FDM组间差异显著(P<0.01)。自身对照组TIMP-2 mRNA表达水平较同龄正常对照组存在下调趋势,但组间无统计学差异(P>0.05)。结论 后极部巩膜TIMP-2表达抑制极可能作为导致巩膜ECM主动重塑的始发因素之一而参与FDM形成。

形觉剥夺性近视豚鼠巩膜形态及TGF-β_2表达的变化

目的:观察形觉剥夺性近视豚鼠巩膜组织学改变和TGF-β2在巩膜中的表达。方法:用头套形觉剥夺右眼的方法诱导近视动物模型,实验前后检测豚鼠双眼屈光状态及眼轴长度。HE染色观察后极部巩膜形态学改变,免疫组织化学法对TGF-β2在巩膜内的表达进行定性及半定量测定。结果:实验组巩膜变薄、胶原纤维排列紊乱,粗细不均,纤维间隙变大,纤维走向不一,板层结构不清;巩膜TGF-β2表达明显下调。结论:形觉剥夺性近视眼的巩膜产生一系列的退行性改变,TGF-β2是形觉剥夺性近视形成的重要因素之一。

MK801对近视视网膜NO-cGMP信号通路的调控

目的:观察MK801对豚鼠近视的调节,探讨其在近视发病机制中的作用。方法:3周龄三色豚鼠分为6组:A组(正常空白对照组)、B组(右眼遮盖3周组)、C组(右眼遮盖3周+玻璃体腔生理盐水注射组)、D组(右眼遮盖3周+玻璃体腔注射1 ng MK801组)、E组(右眼遮盖3周+玻璃体腔注射10 ng MK801组)、F组(右眼遮盖3周+玻璃体腔注射100 ng MK801组)。实验前及实验3周时对各组进行视网膜检影和A超测眼轴,原位杂交法检测神经细胞性一氧化氮合酶(ncNOS)的表达,放射免疫法检测cGMP的含量,将D,E,F组的屈光度、眼轴、ncNOS及cGMP含量与MK801药物浓度进行直线相关分析。结果:玻璃体腔药物注射C,D,E,F组遮盖眼随注射浓度的升高近视屈光度数下降,眼轴延长减慢,ncNOS及cGMP含量下调,与MK801注射浓度行相关分析呈直线相关,屈光度与注射浓度呈正相关(r=0.702,P<0.05),眼轴长度、ncNOS表达、cGMP表达与其呈负相关(r=-0.736,-0.637,-0.725,P<0.05)。结论:近视豚鼠MK801玻璃体腔注射能通过下调NO-cGMP表达减缓近视的进展,呈剂量依赖性。

小鸡形觉剥夺性近视眼后极部巩膜MMP-2与TIMP-2 mRNA表达的动态变化

目的 探讨小鸡形觉剥夺性近视眼 (form deprivationmyopia,FDM )后极部巩膜基质金属蛋白酶 2 (matrixmetalloproteinase 2 ,MMP 2 )及其特异性组织抑制剂 (tissuein hibitorofmatrixmetalloproteinase 2 ,TIMP 2 )mRNA表达的时间动态性变化。方法 5 0只 1d龄来亨雏鸡以半透明眼罩分别遮盖右眼 4、7、14、2 1、30d制备FDM动物模型 ,每组10只 ,未遮盖眼为自身对照眼 ,并随机选取同数目同龄小鸡作为正常对照眼。实验前及预定实验时间进行视网膜检影验光和眼轴长度测量。摘除眼球 ,提取后极部巩膜总RNA ,采用一步法逆转录 聚合酶链反应检测每组小鸡后极部巩膜MMP 2、TIMP 2mRNA表达水平。结果 与正常组、自身对照组相比 ,FDM后极部巩膜MMP 2mRNA显著增高 ,TIMP 2mRNA表达明显降低 ,组间差异非常显著 (P <0 .0 1)。随遮盖时间延长 ,MMP 2mRNA表达逐渐上调 ,7～ 2 1d达最高峰 ,以后轻度下降 ,但仍维持于一较高水平 ,不同遮盖时间组间差异显著 (P <0 .0 1) ,而TIMP 2mRNA表达与之相反。自身对照组MMP 2mRNA表达较同龄正常对照组有轻度上调趋势 ,TIMP 2有下调趋势 ,但组间均无统计学差异 (P >0 0 5 )。结论 MMP 2 /TIMP

TGF-β1在鸡形觉剥夺性近视眼中的表达及作用

目的 建立鸡的形觉剥夺性近视眼(FDM)模型,研究视网膜和脉络膜TGF -β1及其mRNA在FDM发展中的表达变化,探讨TGF- β1在FDM中的作用。 方法 取当日出生的来亨鸡 40只,随机遮盖一眼,另眼作对照。实验中测量双眼的屈光度与轴长,RT -PCR检测TGF-β1mRNA的表达,免疫组织化学分析TGF β1的活性。 结果 形觉剥夺可以导致眼球轴性延长,近视屈光度增加。去遮盖后双眼轴长差异减小,近视度下降。形觉剥夺降低视网膜TGF- β1和TGF -β1mRNA的表达,去遮盖后逐渐恢复。 结论 视网膜TGF- β1的变化可能与FDM的形成有关,TGF- β1可能参与眼球生长调控。