Alterations in rabbit retina lipid metabolism induced by detachment. Decreased incorporation of [3H]DHA into phospholipids.
BACKGROUND
Docosahexaenoic acid (22:6n-3, DHA) is found in high concentration in phospholipids from retinal membranes, and is essential for their function. This study investigated the effect of in vivo retinal detachment on in vitro lipid metabolism using [3H]DHA.


METHODS
Rabbit retina was detached from the retinal pigment epithelium by injecting physiological saline into the subretinal space of the eye. Retinal samples from control (non-operated) and sham (operated, no detachment) animals, and from attached and detached retinal areas from the same eye, were incubated in vitro with [3H]DHA for 4 hours, and then prepared for biochemical and autoradiographic analysis.


RESULTS
In control and sham retinas, [3H]DHA was preferentially esterified into phospholipids (82%) with low labeling of free fatty acids (FFA) (5%). In samples from detached areas of the retina, a higher proportion of [3H]DHA was recovered in the FFA pool (up to 30%) and its esterification was shunted into triacylglycerol, thereby reducing the formation of [3H]DHA-phospholipids. Changes were sustained through 48 hours of postdetachment. High labeling of inner segments and synaptic terminals was observed autoradiographically in control retinas, while in detached retinas, clusters of labeling were detected in the neural retina, and eventually within the photoreceptor layer.


CONCLUSIONS
Retinal detachment induces longlasting changes in lipid metabolism which are reflected in lower labeling of [3H]DHA-phospholipids. Metabolic changes, sustained through 48 hours, may lead to inadequate synthesis/turnover of phospholipids, among them, those containing DHA, possibly resulting in defective disc membrane assembly with subsequent deterioration of visual cells.
Santos
F F
FF
LSU Eye Center, Louisiana State University Medical Center School of Medicine, New Orleans 70112-2234, USA.
de Turco
E B
EB
Gordon
W C
WC
Peyman
G A
GA
Bazan
N G
NG
D000818:Animals; D001345:Autoradiography; D004281:Docosahexaenoic Acids / Q000378:metabolism*; D004951:Esterification; D050356:Lipid Metabolism; D010743:Phospholipids / Q000378:metabolism*; D011817:Rabbits; D012160:Retina / Q000378:metabolism*; D012163:Retinal Detachment / Q000378:metabolism*; D013997:Time Factors; D014018:Tissue Distribution; D014280:Triglycerides / Q000378:metabolism
D010743:Phospholipids; D014280:Triglycerides; D004281:Docosahexaenoic Acids