Abstract
Purpose: :
A new semi-automated photocoagulator, pattern scan laser photocoagulator (PASCAL®) has been developed, which is using a scanning laser with pulse duration of 10 to 30 milliseconds. The histological studies revealed that PASCAL® might preserve the inner retina. Previously, we reported that short pulse duration (10-millisecond) showed less expression of VEGF after laser injury compare to conventional (100-milllisecond) laser settings (Hirano Y, et al, ARVO, 2010). The purpose of this study is to evaluate the effect of pulse duration on the expression of inflammatory cytokine in the murine retina after laser photocoagulation.
Methods: :
Retinal scatter laser photocoagulation was performed on C57BL/6J mice with short pulse and high power settings (250 mW, 10 milliseconds, 100µm) using a PASCAL® laser (Topcon, Tokyo) or conventional settings (100 mW, 100 milliseconds, 100 µm) using multicolor laser (Novus Varia®, Lumenis, CA). The eyes were enucleated 1, 3 and 7 days after laser treatment. The level of inflammatory cytokine including MCP-1, RANTES and IL-6 in the sensory retina and RPE-choroid were quantified by ELISA.
Results: :
MCP-1, RANTES and IL-6 were significantly elevated in the sensory retina and RPE-choroid after laser treatment in both groups. On day 1, the RANTES and IL-6 level in the sensory retina significantly increased in PASCAL® group (p<0.05). The MCP-1 level in the sensory retina significantly increased in PASCAL® group 3 days after laser (p=0.02). There was no significant difference in the RPE-choroid.
Conclusions: :
Our data suggest that pulse durations of 10 milliseconds induce less inflammatory cytokine in the sensory retina compare with the conventional 100-millisecond duration. Collectively, short pulse with high power laser photocoagulation, like PASCAL® may prevent macular edema after panretinal photocoagulation.
Keywords: diabetic retinopathy • laser • cytokines/chemokines