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Assessment of Memory Function in Pilocarpine-induced Epileptic Mice
Published on: June 4, 2020
Pilocarpine-induced flare is physiological rather than pathological
Thomas F Freddo1, Nathan Neville, Haiyan Gong
1School of Optometry, University of Waterloo, Canada. tfreddo@uwaterloo.ca
Experimental Eye Research
|November 29, 2012
Summary
Elevated aqueous humor protein (flare) may not always indicate blood-aqueous barrier breakdown. Pilocarpine-induced flare in rabbits resulted from iris protein extrusion, not barrier disruption, challenging traditional views.
Area of Science:
- Ophthalmology
- Physiology
- Cell Biology
Background:
- Elevated aqueous humor protein, or flare, is traditionally considered a sign of blood-aqueous barrier (BAB) breakdown.
- Recent human studies using MRI suggest pilocarpine-induced flare doesn't stem from ciliary body BAB disruption.
Purpose of the Study:
- To investigate the source of pilocarpine-induced aqueous flare in rabbits.
- To determine if pilocarpine causes blood-aqueous barrier breakdown in the iris vasculature or ciliary epithelium.
- To explore alternative mechanisms for pilocarpine-induced flare.
Main Methods:
- Combined cell-flare meter and intravascular horseradish peroxidase (HRP) tracer studies in rabbits.
- Light and electron microscopy to assess vascular permeability.
- Analysis of elutable protein from iris stroma using immunohistochemistry.
Main Results:
- Pilocarpine caused miosis and increased aqueous flare without evidence of BAB leakage in the iris or ciliary body.
- No HRP leakage was observed in the iris vasculature or ciliary epithelium.
- Pilocarpine-treated eyes showed reduced elutable protein in the iris stroma, suggesting protein extrusion.
Conclusions:
- Pilocarpine-induced flare in rabbits is not caused by blood-aqueous barrier breakdown in the ciliary body or iris vasculature.
- Flare may originate from the extrusion of protein reservoirs within the iris stroma.
- These findings challenge the assumption that all clinical flare indicates BAB disruption.
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