Scleral calcification and photoreceptor cell death during aging and exposure to chronic stress.
Male and female Fischer 344 rats of three different ages (12, 18, and 25 months) have been examined for the presence of photoreceptor (PR) cell loss and for occurrence of scleral cartilage and bone formation. In addition, male and female rats, aged 11 months at the beginning of the experiments, were exposed to chronic stress for either 0.5, 2, 4, or 6 months. Photoreceptor cell death gradually increases during the aging process and is exacerbated by exposure to chronic stress. It is more severe in the peripheral than the central retina and exposure to stress increases this pattern of cell loss. The superior retina is more severely affected than the inferior hemisphere in aging and during stress. The incidence of scleral cartilage or bone formation increases with age in male and female rats, but with stress exposure an increase is seen in males only. Bone formations occur more frequently in male than in female animals and are almost always (97%) located in the superior hemisphere of the eye. Although there appears to be a direct relationship between photoreceptor cell death and the occurrence of scleral ossifications in group data, in individual eyes the bone formations are not always associated with severity of PR cell loss. The relationship of PR cell death and incidence of scleral ossification to gender and to exposure to stress supports a hypothesis for an endocrine basis of ocular aging.
O'Steen
W K
WK
Department of Neurobiology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, NC 27103.
Brodish
A
A
D000375:Aging / Q000378:metabolism / Q000473:pathology*; D000818:Animals; D001775:Blood Circulation / Q000502:physiology; D002114:Calcinosis / Q000378:metabolism / Q000473:pathology*; D002119:Calcium Carbonate / Q000378:metabolism; D002129:Calcium Oxalate / Q000378:metabolism; D002130:Calcium Phosphates / Q000378:metabolism; D002470:Cell Survival; D005123:Eye / Q000378:metabolism / Q000473:pathology*; D005128:Eye Diseases / Q000378:metabolism / Q000473:pathology; D005260:Female; D006651:Histocytochemistry; D008297:Male; D009799:Ocular Physiological Phenomena; D010786:Photoreceptor Cells / Q000473:pathology*; D051381:Rats; D011916:Rats, Inbred F344; D012160:Retina / Q000378:metabolism / Q000473:pathology / Q000502:physiology; D012598:Sclerosis / Q000473:pathology; D013312:Stress, Physiological / Q000378:metabolism / Q000473:pathology*
D002130:Calcium Phosphates; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; D002129:Calcium Oxalate; C485838:calcium phosphate, monobasic, anhydrous; C020243:calcium phosphate; D002119:Calcium Carbonate; C485829:calcium phosphate, dibasic, anhydrous