Quantitative research on effects of pyrrolidine dithiocarbamate on the aqueous flare in a PVR model with LFCM

AIM: To study the inhibitory effect of pyrrolidine dithiocarbamate (PDTC) on the inflammatory reaction in an experimental proliferative vitreoretinopathy (PVR) model with laser flare cell meter (LFCM). METHODS: A total of 20 pigmented rabbits were divided into two groups randomly, with 10 rabbits in each group. After the creation of retinal holes, 0.1mL PDTC was injected intravitreally into the right eyes of Group 1 (A1) and the left eyes of Group 1 (A2), and 0.1mL balanced saline solution (BSS) into the right eyes of Group 2 (B1). One hour later, 0.1mL BSS was injected into the eyes of A1, and 5000U IL-1 beta in 0.1mL BSS was injected intravreally into the eyes of A2 and B1. Clinical evaluation and LFCM examination were performed before retinal injury (PO) and at 4, 24 hours, 1, 2 and 4 weeks after the second injection (P4h, P24h, P1wk, P2wk and P4wk). Histopathologic and immunohistochemical examination were also performed at these time points. RESULTS: PDTC could inhibit the inflammatory reaction obviously from P24h to P2wk. The eyes of A1 and A2 recovered earlier than those of B1. Although inflammatory reaction in the 3 groups resolved completely by the end of P2wk measured with the slit-lamp microscope, the eyes of 81 still showed obvious aqueous flare judged by the LFCM compared with those of A1 and A2. Histopathologic and immunohistochemical examination showed that nuclear factor-kappa B (NF-kappa B) was activated by IL-1 beta and the PDTC had inhibitory effect on it without obvious toxicity to retina. CONCLUSION: Inflammatory reaction is involved in the rabbit model of PVR induced by injecting intravitreally IL-1 beta and the PDTC can relieve it significantly. The LFCM provides a new, sensitive, objective and non-invasive method to quantify the inflammatory reaction in the PVR model.