Expression Of HSP47 In Form-deprived Myopic Sclera

Objective: This study was to investigate the expression of HSP47 on form-deprive myopic sclera in guinea pig and explore the impact of HSP47 on collagen remodeling in myopic sclera.and to provide theoretical basis for the following study and development of therapeutic method for myopia aiming to HSP47.Methods: 48 guinea pigs(two weeks old,Male and female unlimited)were selected without eye disease.guinea pigs were randomly divided in to normal control group(16guinea pigs)and FDM group(32guinea pigs).Monocular FDM was induced by occluding the right eyes of guinea pigs in FDM group with translucent latex balloons for 2,4 weeks,respectively,and consecutive occluding for 10 days followed by uncovering for 4 days,the other group consecutive occluding for 24 days followed by uncovering for 4 days.The refractive power was detected by retinoscopy and axial length was measured with Vernier caliper.The histological analysis was applied to assess the posterior sclera changes;Quantitativereal-time polymerase chain reaction(qPCR);western Boltting(WB)was used to were employed to detect the dynamic expression of type I collagen,Matrix Metalloproteinase 2(MMP-2),Tissue Inhibitors of Metalloproteinase1(T IMP-1),Tissue Inhibitors of Metalloproteinase1(TIMP-2)and Hsp47 protein ad mRNA in the sclera of guinea pigs with emmetropia and experimental myopia.Results:(1)Refraction and ocular axis:The refraction was hypermetropic in both normal contral groups occluding of eyes(P>0.05)。In the FDM groups,after occluding 2,4 weeks,10 days followed by uncovering for 4 days,and 24 days followed by uncovering for 4 days,the Refraction power was increased to(-1.88±0.52),(-2.46±0.58),(-1.92±0.41),and(-2.83±0.72)D,and the axial length was increased to(7.21±0.07),(7.7±0.21),(7.32±0.16)and(7.8±0.22)mm.There were statistical differences in both refractive power and axial length over time in the FDM groups from normal contral groups(all at P<0.05).(2)Pathological measurement: Both HSP47 and type I collagen were positively expressed in the posterior sclera of guinea pigs.Compared with the control group at the same time,the expression decreased.(3)The mRNA expression of HSP47 、type I collagen、 MMP2、 TIMP-1、TIMP-2 in the sclera of guinea pigs.was determined by qPCR.The mRNA expression of HSP47 in normal control group,myopia group and recovery group at 4-and 6-week were(0.49±0.19),(0.16±0.16),(0.10±0.06),(1.21±0.56),(0.44±0.26)and(0.26±0.10)respectively.The expression of HSP47 mRNA in the sclera of FDM groubs was significantly lower than those of the control groub in various time points(all P<0.05).The mRNA expression of type I Collagen were(0.65±0.33),(0.31±0.11),(0.22±0.13),(1.39±0.63),(0.43±0.05)and(0.27±0.14)respectively.Compared to normal control,there were statistical differences(all P < 0.05).The mRNA expression of MMP-2 were(0.58±0.19),(1.21±0.53),(1.59±0.82),(1.18±0.25),(2.33±0.11),and(5.81±1.82)respectively.Except myopia groub at 4 week(P=0.77),there were statistical differences between FDM groubs and control group(all P<0.05).The mRNA expression of TIMP-1 were(0.83±0.01),(0.65±0.16),(0.24±0.13),(0.95±0.29),(0.23±0.17)and(0.25±0.17)respectively.Compared to normal control,there were statistical differences(all P<0.05).The mRNA expression of TIMP-2 were(0.68±0.49),(0.11±0.03),(0.20±0.11),(1.61±0.82),(0.70±0.30)and(0.14±0.41)respectively.Compared to normal control,there were statistical differences(all P<0.05).(4)Detection of protein expression of HSP47,type I collagen,MMP-2,TIMP-1by Western blot.The protein exession of HSP47 in normal control group,myopia group and recovery group at 4-and 6-week were(1.42±0.35),(0.66±0.19),(0.44±0.20);(2.05±0.38),(1.11±0.38)and(0.79±0.53)respectively.There were statistical difference between normal control and FDM groups(all P<0.05).The protein expression of type I collagen were(1.18±0.28,(0.61±0.23),(0.35±0.13),(1.68±0.40),(0.82±0.35)and(0.50±0.19)respectively.Compared to normal control,there were statistical differences(all P<0.05).The protein expression of MMP-2 were(0.37±0.10),(0.67±0.21),(1.05±0.40),(0.85±0.18),(1.51±0.30)and(1.91±0.24)respectively.Except myopia groub at 4 week(P=0.82),there were statistical differences between FDM groubs and control group(P<0.05).The protein expression of TIMP-1 were(1.45±0.20),(1.05±0.25),(0.69±0.16),(1.87±0.31),(0.42±0.08)and(0.76±0.25)respectively.Compared to normal control,there were statistical differences(all P<0.05).The protein expression of TIMP-2 were(1.14±0.45),(0.52±0.20),(0.52±0.04),(1.96±0.49),(1.36±0.49)and(0.96±0.23)respectively.Compared to normal control,there were statistical differences(all P<0.05).(5)The postive correlation were found in the expression of HSP47 on the myopia sclera with that of type I collagen in both protein and mRNA levels(mRNA:r=0.807,P<0.001,protein r=o.923,P<0.001)。 Conclusion:(1)Our data showed that there had high expression of HSP47 on myopic sclera。(2)The expression of HSP47 and type I collagen in the sclera are correspondingly weaked in FDM eyes,A consistent expression trend is found between HSP47 and type I collagen.(3)The increase of collagen degradation during myopia formation is not only related to the imbalance between MMPs and TIMPs system,but also to the decrease of HSP47,which makes newly synthesized collagen more sensitive to protease and easier to be hydrolyzed by protease.