[Effects of ammonium pyrrolidine dithiocarbamate (PDTC) on osteopontin expression and autophagy in tubular cells in streptozotocin-induced diabetic nephropathy rat].

Objective: To investigate the effects of ammonium pyrrolidine dithiocarbamate (PDTC) on tubulointerstitial inflammatory molecules and autophagy in diabetic nephropathy (DN) rats. Methods: Twenty-four male Sprague-Dawley rats were assigned to DN group (n=6) and DN+ PDTC group (n=6, PDTC, ip, 100 mg·kg-1·d-1), all received streptozotocin (STZ) 60 mg/kg intraperitoneally, and the other 12 rats were randomly divided into control group (n=6) and PDTC group (n=6). At the end of 12 weeks, after serum creatine (Scr) and 24-hour urinary protein were determined, rats were sacrificed to determined the renal pathological damages and the changes of nuclear factor (NF)-κB p65, p62, osteopontin (OPN), microtubule associated protein 1 light chain 3 (LC3)-Ⅱ/LC3-Ⅰ, nuclear p-NF-κB p65 by immunohistological stainning and Western blot, and ultrastructural changes of autophagic process was observed by electron microscopy (EM). Results: Scr was similar among the four groups (P>0.05). The levels of urinary protein in DN group and DN + PDTC group were significantly higher than the other two groups (all P<0.01), but the level of urinary protein in DN + PDTC group was lower than that of DN group (P<0.05). DN + PDTC group had less tubulointerstitial damage compared with DN group (P<0.05). Among the four groups, expressions of p62, p65, OPN of tubulointerstitial area in DN group were significantly higher than that of the other groups (all P<0.05), and Western blot showed that DN+ PDTC group had less expressions of NF-κB p65, nuclear p-p65, OPN and more expresssion of LC3-Ⅱ/LC3-Ⅰ compared with DN group (all P<0.05), which were consistent with the decreased autophagic vacuoles and increased mitochondria dysfunction revealed by EM. Correlation analysis showed that renal LC3-Ⅱ/LC3-Ⅰ was negatively correlated the expressions of nuclear p-p65 and OPN (r=-0.45, P=0.02; r=-0.50, P=0.01), and p62 was positively correlated the expressions of nuclear p-p65 and OPN (r=0.33, P=0.01; r=0.41, P=0.01). Conclusion: Tubular NF-κB activation is closely related to autophagy dysfunction in DN rats, and PDTC may enhance autophagy activity in tubule cells by blocking NF-κB activity.

Development of diabetic nephropathy in nude mice.

BACKGROUND: Immune dysfunction is very common in diabetes mellitus (DM). However, there is no evidence whether such immune dysfunction can influence the development of DM, especially the development of diabetic nephropathy (DN). AIM: To investigate the influence of absence of T cells on DN. MATERIALS AND METHODS: Balb/c nude mice and Balb/c wild-type nude (WT) mice were injected with streptozotocin (STZ). Serum tumor necrosis factor α (TNF-α), blood glucose, body weight, urine albumin/creatinine ratio and rate of kidney weight to body weight (KW/BW) were measured. RESULTS: After modeling, there was no difference of blood glucose level between nude mice and WT mice except at week 2 (28.3 ± 4.9 mmol/l vs 23.1 ± 3.9 mmol/l, p<0.01). At week 4, the serum TNF- α level of nude mice got to 175.08 ± 46.03 pg/ml (p<0.05, compared with baseline level 80.19 ± 8.46 pg/ml), whereas the TNF- α levels of WT mice was stable. At week 4, the body weight of nude mice was lower than that of WT mice (14.7 ± 3.15 g vs 17.97 ± 2.85 g, p<0.05); the urine albumin/creatinine ratio (Alb/Cr) of nude mice was higher than that of WT mice (50.96 ± 5.57 mg/mmol vs 41.09 ± 5.79 mg/mmol, p<0.05); the kidney weight to body weight of nude mice was higher than that of WT mice (0.01352 ± 0.00163 vs 0.01173 ± 0.00131, p<0.05). Correlation analysis showed urine Alb/Cr positively correlated with serum TNF-α level at week 4 (r = 0.588, p<0.01). At week 4, the increase of type IV collagen in the glomeruli was more prominent in diabetic nude mice than in diabetic WT mice (p<0.05). CONCLUSIONS: Absence of T cells in DM might influence the development of DN.