Duration 5min, Q&A 3min
Safety of Intravitreal Imatinib and Its Efficacy in Inhibition of Experimental Choroidal Neovascularization
To determine the safe dose of intravitreal imatinib, a thyrosine kinase inhibitor, and to evaluate its efficacy in inhibition of experimental choroidal neovascularization in a rat model.
86 pigmented male rats, weights 200-300 gram, from Razi vaccine and serum research institute were included.
Phase I: 55 pigmented rats, were included and divided into 6 groups. Each rat received an intravitreal imatinib injection with Hamilton Syringes in the right eye. The dose of imatinib was 330µg/5µl, 250µg/5µl, 165µg/5µl, 80µg/5µl and 40µg/5µl in groups 1, 2, 3, 4 and 5 respectively. In group 6, 5µl of balanced salt solution (BSS) was injected. Electroretinography (ERG), both scotopic and photopic, was performed at the baseline and 1 week and 4 weeks after drug delivery in all rats. 4 weeks after imatinib injection, all rats were sacrificed and their eyes were enucleated and sent for histopathology evaluation.
Phase II: 31 rats were included; experimental CNV was induced by laser photocoagulation in the right eye of all rats. In 21 rats, the highest safe dose of imatinib (determined in phase I) was injected intravitreally. BSS was injected in 10 other rats. After 4 weeks, fluorescein angiography was performed, then the rats were sacrificed, and their eyes were sent for histopathologic evaluation.
Results and Conclusion
Phase I: According to the histopathologic findings and GFAP(glial fibrillary acidic protein) results only 80µg/5µl and 40 µg/5µl dosages of intravitreal imatinib were safe. In addition, there was no statistically significant difference in the scotopic and photopic responses when ERG results were compared in each group. (P> 0.05)
Phase II: According to the angiographic, histopathological and GFAP results, 80 µg/5µl of intravitreal imatinib was not effective in inhibition of experimental CNV formation compared with the placebo.
In conclusion, intravitreal imatinib is not effective in inhibition of experimental CNV in a rat model.
[ Keyword ]
Intravitreal imatinib / Rat / Experimental CNV / GFAP
[ Conflict of Interest ]