Upregulated expression of neurocan, a nervous tissue specific proteoglycan, in transient retinal ischemia.
OBJECTIVE
Neurocan, a nervous tissue-specific chondroitin sulfate proteoglycan synthesized primarily by neurons, is expressed abundantly in developing rat retina, whereas it is rarely expressed in adult rat retinas. This study investigated the reexpression of neurocan in a pathologic condition of adult rat retina.


METHODS
Transient retinal ischemia was produced by occlusion of the retinal artery for 60 minutes. After transient retinal ischemia, neurocan expression was investigated by reverse transcription-initiated polymerase chain reaction (RT-PCR), immunohistochemistry, and immunoblot analysis.


RESULTS
Semiquantitative analysis using RT-PCR revealed that mRNA expression for neurocan increased at 24 hours after reperfusion. Furthermore, on immunoblot analysis using an anti-neurocan antibody, MAb 1G2, the intensity of the 220-kDa band as well as the 150-kDa band increased markedly at 24 and 72 hours after reperfusion. The 220-kDa band was predominant at 24 hours after reperfusion, whereas the intensity of the 150-kDa band became almost the same as that of the 220-kDa band at 72 hours after reperfusion. Immunohistochemical analysis revealed that upregulated neurocan immunoreactivity was associated with glial Müller cells.


CONCLUSIONS
Thus, upregulated expression of neurocan in transient retinal ischemia was demonstrated. Furthermore, the immunohistochemical analysis revealed that the upregulated expression of neurocan is derived from Müller cells, although it has been thought that neurocan is synthesized by neurons so far. The neurocan expression by Müller cells suggests that this proteoglycan plays a role in the damage and repair processes in diseased retina.
Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Japan.
M
M
Inatani
H
H
Tanihara
A
A
Oohira
M
M
Honjo
N
N
Kido
Y
Y
Honda
D000818:Animals; D011508:Chondroitin Sulfate Proteoglycans / Q000096:biosynthesis* / Q000235:genetics; D017931:DNA Primers / Q000737:chemistry; D005136:Eye Proteins / Q000096:biosynthesis* / Q000235:genetics; D019084:Fluorescent Antibody Technique, Indirect; D015870:Gene Expression; D015151:Immunoblotting; D007511:Ischemia / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D037181:Lectins, C-Type; D008297:Male; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000235:genetics; D058580:Neurocan; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D015356:Retinal Artery Occlusion / Q000150:complications; D012164:Retinal Diseases / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D012171:Retinal Vessels / Q000378:metabolism* / Q000473:pathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation
D011508:Chondroitin Sulfate Proteoglycans; D017931:DNA Primers; D005136:Eye Proteins; D037181:Lectins, C-Type; D009419:Nerve Tissue Proteins; D058580:Neurocan; D012333:RNA, Messenger; C076817:NCAN protein, human