Changes of neurotrophin-3 expression in normal and pigemental degeneration retina

Objective To study the changes of neurotrophin-3(NT-3) in retina from rd mouse with retinal degeneration and from normal C57BL mouse for comparison at postnatal 0～4 week respectively, and to investigate the early characters of development and growth of retina,the expressing rule and the role of NT-3 in the development and degeneration of retina.Methods About 8 to 10 mouse from rd group and C57BL group at postnatal 0～4 week were used respectively. After death,mouse eyeballs were extracted immediately, slices with 4 μm thickness were made from retina,NT-3 contents in retina from different kinds of mouse and at different times were analyzed by immunohistochemistry,photomicroscope and semi-quantitative analysis.Results At postnatal 2 week, ten-layer structures of retina from both rd and C57BL mice could be seen,which in rd mice were not the same as those in C57BL mice.At postnatal 3 week,inner and outer nuclear layers(INL and ONL) of retina were degenerated to only one layer in rd mouse,while the two layers of retina in C57BL mice could be seen clearly.In retina of C57BL mice,NT-3 expression could be found within INL,ONL,inner plexiform layer (IPL) and ganglion cell layer(GCL),while it could only be found within IPL and GCL in retina of rd mice.Within postnatal 0,1 week,content of NT-3 in retina from rd mice were lower than those from C57BL mice(P0.05).The curve of NT-3 contents in retina from rd mice(GCL) were dropped at postnatal 0 week but rose in C57BL mice.Conclusion As far as growth and development is concerned,ten-layer structures of retina in normal mouse can reach an important stage at postnatal 2 week and typical ten-layer structures of retina can be observed at postnatal 3 week;while ten-layer structures of retina in rd mouse can also reach an important stage at postnatal 2 week but its INL and ONL degenerate rapidly at postnatal 3 week.As far as distribution is concerned,NT-3 can be found within ONL,INL,IPL and GCL in retina of normal mouse;while as it can only be found in IPL and GCL of rd mouse.As far as expression is concerned,higher NT-3 expression can be found in retina of normal mouse at postnatal 1,4 week;while higher NT-3 expression can only be found at postnatal 4 week in retina of rd mouse.