Retinal changes in Hemiparkinson rat

Abstract

 

Purpose

 

Parkinson’s disease (PD) is a progressive, multisystem neurodegenerative disorder and dopamine deficiency of the nigrostriatal system is still regarded as the major problem. Visual symptoms are common in PD, ranging from complaints of dry eyes and reading difficulties, through to perceptual disturbances and complex visual hallucinations. Dopaminergic deficiency with loss of a subset of retinal amacrine cells were reported in various PD animal models. However, there are few studies about retinal changes in animal PD model using 6-hydroxydopamine(6-OHDA). Therefore current study investigates the retinal changes in unilateral 6-OHDA-induced rat model of PD

 

Methods

 

PD rat model was established by injection of 6-OHDA into right substantia nigra. . At 2 weeks after surgery, only animals passed the rotation test were included in model group and compared with normal control group. Retinal tissue was collected in ipsilateral and contralateral eye of PD model group and either eye in control group and prepared for immunohistochemistry. The antibodies applied in immunohistochemistry were anti-TH(1:1000), anti-b-NOS(1:5000), anti parvalbumin (1:1000), calbindin(1:2000), and anti PKC-A (1:1000).

 

Results

 

The number of dopaminergic amacrine neurons was significantly decreased in ipsilateral and contralateral retina compared to control. The immunoreativities seen at the border of outer plexiform layer and inner plexiform layer were also decreased in both eyes of PD model compared to control model. AII amacrine neurons and rod bipolar cells in both eyes in PD model showed irregular arrangement and loss of axons in immunohistochemistry using parvalbumin and PKC-a, respectively.

 

Conclusions

 

In hemiparkinson animal model using 6-OHDA, both ipsilateral and contralateral retinas showed structural and functional changes involving dopaminergic amacrine cells, AII amacrine cells and rod bipolar cells.

 

 

Dopaminergic amacrine cells(DA) expressing anti-TH(tyrosine hydoxylase) in control group. Bright processes throughout the entire inner plexiform layer(IPL, dotted arrow)and outer plexiform layer (OPL, solid arrow)

 

 

Dopaminergic amacrine cells(DA) expressing anti-TH(tyrosine hydoxylase) in Parkinson model. The cell size of DA is slightly smaller than control group. Decreased immunoreactivities are noted in inner and outer plexiform layer

 

Keywords: 637 pathology: experimental • 695 retinal degenerations: cell biology