[Protective effects of 15-methyl-lipoxin A4 on mesangioproliferative nephritis in rats].

OBJECTIVE: To investigate the protective effects of 15-methyl-lipoxin A4 (LXA4) on mesangioproliferative nephritis in rats and the possible mechanisms. METHODS: Mesangioproliferative nephritis was induced by a single intravenous injection of the mouse monoclonal anti-Thy1.1 antibodies (ER4) in 20 rats. Ten nephritic rats were injected with 15-methyl-LXA4 at 10 minutes before ER4 antibody injection and then 8-hourly until the rats were sacrificed on day 4 after nephritis induction. The nephritis was evidenced by presence of proteinuria, histologic examination with light microscopy, infiltrating leukocyte assessed by immunofluorescence microscopy, and mesangial cell proliferation assessed by proliferation scoring and by immunohistochemical staining of proliferating cell nuclear antigen (PCNA). Expressions of interleukin (IL)-1beta and IL-6 protein or mRNA in glomeruli were determined by radioimmunoassay or RT-PCR, respectively. Phosphorylated phosphoinositide 3-kinase (PI3-K), Akt1 and p27(kip1) in glomeruli were analyzed by Western Blot. Activities of nuclear factor-kappaB (NF-kappaB) and signal transducer and activator of transcription 3 (STAT3) in glomeruli were assessed by electrophoretic mobility shift assay (EMSA). RESULTS: There were increases in glomerular infiltration of leukocyte, expressions of IL-1beta and IL-6 protein and mRNA, and activities of NF-kappaB in nephritic rats between days 1 and 4 after nephritis induction. The enhanced proteinuria, score of mesangial proliferation, glomerular PCNA positive cells, activities of phosphorylated PI3-K, Akt1 and STAT3, and reduced p27(kip1) expression were found on day 4 after nephritis induction. 15-Methyl-LXA4 treatment significantly reduced the proteinuria, glomerular infiltration of leukocyte, expressions of IL-1beta and IL-6 protein and mRNA, score of mesangial proliferation, glomerular PCNA positive cells, activities of phosphorylated PI3-K, Akt1, NF-kappaB and STAT3, and increased the p27(kip1) expression. CONCLUSIONS: 15-Methyl-LXA4 can markedly inhibit the proteinuria, glomerular inflammation, and mesangial cell proliferation induced by anti-Thy1.1 antibodies. The inhibition effects are related to PI3-K/Akt1/p27(kip1)/cyclin pathway, STAT3 and NF-kappaB pathway-dependent signal transduction.

[Effects of colchicine on synthesis and excretion of cytokines and extracellular matrix by human renal fibroblasts].

OBJECTIVE: Renal interstitial fibrosis is the final common pathway leading to end-stage renal failure for progressive renal disease of various types. The present study was undertaken to add to the knowledge on colchicine's antiinflammatory and antifibrotic properties confirmed by both human and experimental studies. As the main effector cells, fibroblasts have a central role in the pathogenesis of renal fibrosis. This study aimed to investigate the effects of colchicine on the synthesis and excretion of cytokines transforming growth factor-beta1 (TGF-beta1), interleukin-1beta (IL-1beta) and extracellular matrix (collagen III, collagen IV) in human renal fibroblast. METHODS: Various concentrations of colchicine (5.0 micromol/L, 10.0 micromol/L, 20.0 micromol/L, 40.0 micromol/L) were used to pretreat human embryo renal fibroblasts for 1 hour which were cultured in vitro and then stimulated by 10.0 microg/ml of lipopolysaccharide (LPS). After 18 hours, these fibroblasts and their supernatant were collected. The expression of TGF-beta1 mRNA, IL-1beta mRNA in the cells was studied by using RT-PCR, and the excretion of TGF-beta1, IL-1beta, collagen III and collagen IV by the fibroblasts was assessed by ELISA respectively. RESULTS: (1) By pure stimulation with 10.0 micro g/ml LPS, the expression of TGF-beta1 mRNA and IL-1beta mRNA of fibroblasts was up-regulated 3 times (66.1 +/- 1.6 vs. 22.3 +/- 2.0, q = 590.5, P = 0.002) and 4.7 times (22.0 +/- 2.2 vs. 4.7 +/- 0.8, q = 106.8, P = 0.009), respectively. The protein excretion of TGF-beta1 and IL-1beta was remarkably increased as well compared with the control group [TGF-beta1: (516 +/- 14) pg/ml vs. (420 +/- 5) pg/ml (q = 80.3, P = 0.012), IL-1beta: (3.4 +/- 0.3) pg/ml vs. (0.3 +/- 0.1) pg/ml (q = 297.9, P = 0.003)]. (2) Colchicine could inhibit the expression of TGF-beta1 mRNA and protein in a dose-dependent manner. IL-1beta mRNA and protein were both up-regulated by colchicine. (3) LPS could not stimulate the excretion of extracellular matrix by fibroblasts, but the excretion of collagen III and collagen IV was down regulated by colchicine in a dose-dependent manner. CONCLUSION: (1) The expression of TGF-beta1 mRNA and the excretion of TGF-beta1 protein in the fibroblasts was significantly suppressed by colchicine, while the expression of IL-1beta mRNA and the excretion of IL-1beta protein were enhanced. (2) Colchicine has significant inhibitory effect on the excretion of extracellular matrix such as collagen III and collagen IV in fibroblasts.