title: The effects of actomyosin disruptors on the mechanical integrity of the avian crystalline lens.
abstract: OBJECTIVE
  Actin and myosin within the crystalline lens maintain the structural integrity of lens fiber cells and form a hexagonal lattice cradling the posterior surface of the lens. The actomyosin network was pharmacologically disrupted to examine the effects on lenticular biomechanics and optical quality.
  
  
  METHODS
  One lens of 7-day-old White Leghorn chickens was treated with 10 µM of a disruptor and the other with 0.01% dimethyl sulfoxide (vehicle). Actin, myosin, and myosin light chain kinase (MLCK) disruptors were used. The stiffness and the optical quality of the control and treated lenses were measured. Western blotting and confocal imaging were used to confirm that treatment led to a disruption of the actomyosin network. The times for the lenses to recover stiffness to match the control values were also measured.
  
  
  RESULTS
  Disruptor-treated lenses were significantly less stiff than their controls (p≤0.0274 for all disruptors). The disruptors led to changes in the relative protein amounts as well as the distributions of proteins within the lattice. However, the disruptors did not affect the clarity of the lenses (p≥0.4696 for all disruptors), nor did they affect spherical aberration (p = 0.02245). The effects of all three disruptors were reversible, with lenses recovering from treatment with actin, myosin, and MLCK disruptors after 4 h, 1 h, and 8 min, respectively.
  
  
  CONCLUSIONS
  Cytoskeletal protein disruptors led to a decreased stiffness of the lens, and the effects were reversible. Optical quality was mostly unaffected, but the long-term consequences remain unclear. Our results raise the possibility that the mechanical properties of the avian lens may be actively regulated in vivo via adjustments to the actomyosin lattice.
authors: School of Optometry and Vision Science, University of Waterloo, Ontario, Canada.
authors: Gah-Jone
authors: GJ
authors: Won
authors: Department of Integrative Biology, University of Guelph, Guelph, Canada.
authors: Douglas S
authors: DS
authors: Fudge
authors: School of Optometry and Vision Science, University of Waterloo, Ontario, Canada.
authors: Vivian
authors: V
authors: Choh
mesh_terms: D000199:Actins / Q000037:antagonists & inhibitors / Q000378:metabolism; D000205:Actomyosin / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D030161:Avian Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D001381:Azepines / Q000494:pharmacology*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology*; D002645:Chickens; D019245:Compressive Strength / Q000187:drug effects; D006244:Hardness / Q000187:drug effects; D006576:Heterocyclic Compounds, 4 or More Rings / Q000494:pharmacology*; D007908:Lens, Crystalline / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D009219:Myosin-Light-Chain Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism; D009218:Myosins / Q000037:antagonists & inhibitors / Q000378:metabolism; D009281:Naphthalenes / Q000494:pharmacology*; D053778:Thiazolidines / Q000494:pharmacology*; D046509:Tissue Culture Techniques
chemical_list: D000199:Actins; D030161:Avian Proteins; D001381:Azepines; D019086:Bridged Bicyclo Compounds, Heterocyclic; D006576:Heterocyclic Compounds, 4 or More Rings; D009281:Naphthalenes; D053778:Thiazolidines; C070571:ML 7; C472645:blebbistatin; D000205:Actomyosin; D009219:Myosin-Light-Chain Kinase; D009218:Myosins; C037067:latrunculin A