title: TIMP-1 production by bovine retinal pigment epithelial cells increases in response to cyclic mechanical stretch.
abstract: 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.
authors.affiliation: Department of Ophthalmology, Okayama University Medical School, Okayama City, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: T
authors.initials: T
authors.lastname: Matsuo
authors.forename: F
authors.initials: F
authors.lastname: Shiraga
authors.forename: H
authors.initials: H
authors.lastname: Ohtsuki
mesh_terms: 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
chemical_list: 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