Increased expression of TSPO-VDAC complex is correlated with NLRP3 inflammasome activation in diabetic retinopathy

The present study aimed to investigate the level of translocator protein (TSPO) and its correlation with different inflammatory cytokines in diabetic retinopathy (DR) patients. Peripheral blood samples were obtained from 54 DR patients and 22 age-related cataract (ARC) patients. The mRNA expression of TSPO, voltage-dependent anion channel (VDAC), apoptosis-associated speck like protein with a caspase recruitment domain (ASC), NOD-like receptors pyrin domain-containing 3 (NLRP3) and caspase-1 were examined by reverse transcription-quantitative PCR. Interleukin-1β and interleukin-18 levels were detected by enzyme-linked immunosorbent assay. The mRNA levels of TSPO, VDAC, ASC, NLRP3 and capase-1, the protein levels of IL-β and IL-18 were all significantly higher in the DR group compared with those in the ARC group. The expression levels of those aforementioned cytokines/proteins were more significantly higher in the subgroup of active proliferative DR (PDR) compared with those in the inactive PDR group (P<0.05). Significant positive correlations between TSPO/VDAC complex and ASC, NLRP3, capase-1, IL-β and IL-18 were found in DR patients. These outcomes suggested that TSPO/VDAC complex and NLRP3 inflammasomes may play an important role in the development and progression of DR.