TIMP-1 production by bovine retinal pigment epithelial cells increases in response to cyclic mechanical stretch.
OBJECTIVE
The effect of mechanical stretch was examined on cultured retinal pigment epithelial (RPE) cells in order to observe changes in their production of tissue inhibitor of metalloproteinase-1 (TIMP-1) and vascular endothelial growth factor (VEGF) in response to physiological strain.


METHODS
Bovine RPE cells in near-confluent culture were exposed to mechanical stretch of the bottom of a 6-cm petri dish at the maximum magnitude of 4500 microstrain and at a cycle of 30 seconds for 72 hours. TIMP-1 and VEGF levels in the medium following 24, 48, and 72 hours of cyclic stretch were measured by enzyme immunoassay.


RESULTS
The growth of RPE cells during the 72-hour period of stretching did not show a significant difference from that of nonstretched control cells. RPE cells in the stretched group produced a significantly larger amount of TIMP-1 at 48 and 72 hours after stretch, compared with nonstretched control (P =.044 and P =.027, respectively, Student t-test). The levels of VEGF produced by RPE cells were not significantly different between the stretched group and nonstretched control group.


CONCLUSIONS
The secretion of TIMP-1 by bovine RPE cells was enhanced by cyclic mechanical stretch. Mechanical strain is one factor in regulating the secretion of TIMP-1 by RPE cells.
Yamaguchi
K
K
Department of Ophthalmology, Okayama University Medical School, Okayama City, Japan.
Matsuo
T
T
Shiraga
F
F
Ohtsuki
H
H
D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D016228:Endothelial Growth Factors / Q000096:biosynthesis; D007124:Immunoenzyme Techniques; D008222:Lymphokines / Q000096:biosynthesis; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000378:metabolism*; D011480:Protease Inhibitors / Q000378:metabolism*; D013314:Stress, Mechanical; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000096:biosynthesis*; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D008222:Lymphokines; D011480:Protease Inhibitors; D019715:Tissue Inhibitor of Metalloproteinase-1; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors