Immunolocalization of transforming growth factor-alpha and its receptor in the normal and hyperoxia-exposed neonatal rat retina.
OBJECTIVE
Transforming growth factor-alpha (TGF-alpha) is a mitogenic polypeptide for a variety of different cells types including retinal neurons and glial cells. We have examined the temporal and spatial expression of TGF-alpha and its receptor in the normal and hyperoxia-exposed neonatal rat retina to determine if the expression is consistent with a role in retinal development and response to retinal injury.


METHODS
We have used immunohistochemistry to examine TGF-alpha and epidermal growth factor receptor (EGF-R) on postnatal days (1, 5, 10, 14, 18, and 25). To examine TGF-alpha and EGF-R expression after retinal injury we studied the retinas from rats which were exposed to 80% oxygen for 10 days and then recovered in room air. Immunolocalization of type IV collagen was performed to examine the retinal vasculature development after hyperoxia.


RESULTS
The pattern of TGF-alpha and EGF-R expression in the neural retina evolved from a diffuse pattern on postnatal day 1 to restricted sites on postnatal day 14. The TGF-alpha immunoreactivity was consistent with localization in Müller cells on postnatal day 14. Both TGF-alpha and EGF-R patterns were altered in the retinas from rats that had been exposed to hyperoxia and recovered in room air for 4 days. The type IV confirmed immunostaining confirmed vaso-obliteration in the deep layer of retinal vessels after hyperoxia.


CONCLUSIONS
Our findings of altered expression of TGF-alpha and EGF-R during retinal development suggests a biological function for this growth factor, possibly promoting retinal cell proliferation, differentiation, and survival. The altered immunolocalization of TGF-alpha and EGF-R in the hyperoxia-exposed retina suggest that TGF-alpha is likely involved in the retinal response to injury.
Powers
M R
MR
Department of Pediatrics, Oregon Health Sciences University, Portland 97201, USA.
Planck
S R
SR
D000818:Animals; D000831:Animals, Newborn; D002455:Cell Division; D003094:Collagen / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism*; D018496:Hyperoxia; D007150:Immunohistochemistry; D010100:Oxygen / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000187:drug effects / Q000378:metabolism*; D016211:Transforming Growth Factor alpha / Q000378:metabolism*
D016211:Transforming Growth Factor alpha; D003094:Collagen; D066246:ErbB Receptors; D010100:Oxygen