Purpose
For chronic eye diseases such as age-related macular disease, controlling the drug release to prolong its effects, as well as discovering new therapeutic agents, is critical. In this study, we inspected a device fabrication for controlled release of clotrimazole (CLT), which was selected through screening of drug libraries as a potential candidate for retinal neuroprotection, and evaluated the controlled release and the in vitro/in vivo effects of CLT-loaded devices against oxidative-induced cell death.
Methods
We investigated the sustained release of CLT by our polymeric device reported previously, besides to elucidate the mechanisms/pathways involved in the neuroprotective effect of CLT, a viability assay under oxygen and oxygen/glucose deprivation (OD/OGD), ROS detecting assay, western blotting on the phosphorylated form of MAPKs, and cleaved caspase-3 were performed. Moreover, to study the possible inhibitory effects of CLT-loaded devices against in vivo light-induced retinal damage, electroretinograms (ERGs) were recorded and western blotting was done.
Results
In vitro results showed pretreatment of RGC5 and RPEJ cells with 10, 20, and 50 µM CLT could decrease the number of cell death, attenuate the percentage of ROS positive cells, and decrease the protein levels of phosphorylated p38, phosphorylated ERK1/2, phosphorylated JNK, and also cleaved caspase-3. In vivo results showed that the CLT-loaded device precluded the reduction of electroretinographic amplitudes after light exposure as observed by the significant increase in the amplitudes of a- and b-waves in the P40-coverd device. Besides, western blotting of retinal samples demonstrated that the CLT-loaded device diminished the protein level of p-p38 and p-ERK1/2 significantly.
Conclusions
In summary, the present study revealed that CLT could protect RGC-5 and RPE-J cells against OD/OGD-induced oxidative stress. This protections can be associated with the effect of CLT in restraining the generation of ROS; inhibiting the phosphorelation of MAPKs, and finally suppressing caspase-3 activity. Furthermore, we established a sustained release system of CLT and demonstrated its evidence of retinal neuroprotective effects. These findings might illuminate the application of our polymeric CLT-loaded device as a promising method for the treatment of retinal ischemia.
Keywords: 412 age-related macular degeneration •
503 drug toxicity/drug effects •
426 apoptosis/cell death