Effects Of PDTC On Osteopontin Expression And Autophagy In Tubular Cells In Streptozotocin-Induced Diabetic Rat

Objective: As an important chronic complication in diabetes, diabetic nephropathy (DN) is a leading cause of end-stage renal failure. It has important significance to study the molecular mechanism of DN progression. It is clear that inflammatory cytokines such as nuclear factor-kappaB (NF-κB), osteopontin (OPN) promote high-glucose-induced renal tubular epithelial cell dmages. Recent studies reported that OPN which regulated by NF-κB inhibite the autophagy in lung cancer. But few study has shown the interaction between NF-κB and autophagy in renal tubular epithelial cells. The present study aimed the effects of pyrrolidine-dithio-carbamate ammonium (PDTC) on tubulointerstitial inflammatory molecules osteopontin (OPN) and autophagy in DN rats.Methods: Twenty-four male Sprague-Dawley rats were randomly assigned to DN group (n=6) and DN+PDTC group (n=6, PDTC, ip,100mg·kg-1·d-1), all received STZ60mg/kg intraperitoneally, and the other12were randomly divided into control group (n=6) and PDTC group (n=6). At the end of8and12weeks, after Scr and24-hour urinary protein were determined, rats were sacrificed for the detection of NF-κB p65, OPN expression, and the changes of LC3expression and autophagy.Results:Scr were similar among the four groups. The levels of urinary protein in DN group and DN+PDTC group were significantly higher than the other two groups, and its level in DN+PDTC group was lower than DN group (P<0.05). DN+PDTC group had less NF-κB p65, nuclear p-p65, OPN expression compared with DN group (all P<0.05). LC3-positive particles in DN+PDTC group was significantly higher than the one in DN group [(12±6)/cell vs (5±2)/cell, P<0.05], but lower than control group and PDTC group [(19±6)/cell,(17±8)/cell, respectively, all P <0.05], finding of the decreased autophagic vacuoles and damaged mitochondria by electron microscope in DN+PDTC group is more apparently improve than DN group. Correlation analysis showed that the number of LC3-positive particles in renal tubular was negatively correlated the nuclear p-p65and OPN expression (r=0.45, P=0.02; r=0.50, P=0.01).Conclusion: Tubular NF-κB activation is closely related to autophagy dysfunction in DN, and PDTC, by blocking NF-κB activity, may suppressed inflammation, enhanced autophagy activity in tubule cells and relieved tubulointerstitial lesions.