Veterinary Surgery 2014-08-01

The effect of photodynamic therapy on cisterna chyli patency in rats.

Eric A Rowe, Kyle G Mathews, Keith E Linder, Lloyd P Tate

Index: Vet. Surg. 43(6) , 642-9, (2014)

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Abstract

To radiographically and histologically evaluate the effects of photodynamic therapy on the cisterna chyli in rats.Experimental study.Adult male Sprague-Dawley rats (n = 60).Cecal lymph nodes were injected with the photodynamic compound verteporfin. A 690 nm, 500 mW diode laser was then directed at the area of the cisterna chyli for either 0, 1.5, or 3 minutes. Cisterna chyli patency was evaluated using lymphography, and histologic changes were evaluated on postoperative Days 1, 3, 5, 7, and 14.Histologically, minimal to marked injury to the cisternal and/or pericisternal tissues was present in all treated rats at all time periods. Radiographically, 8/20 cisternae were occluded in the 1.5-minute treatment group (including 1/4 on Day 1, 2/4 on Day 3, 3/4 on Day 5, 0/4 on Day 7, and 2/4 on Day 14), and 9/20 cisternae were occluded in the 3-minute treatment group (including 0/4 on Day 1, 1/4 on Day 3, 3/4 on Day 5, 3/4 on Day 7, and 2/4 on Day 14). There was minimal to no histologic evidence of tissue injury in control rats. All control cisternae were radiographically open.Further investigations into the timing of laser application and light dose, or alternative photodynamic agents are required to limit injury to adjacent tissues and to improve the effectiveness of cisternal photoablation.© Copyright 2014 by The American College of Veterinary Surgeons.