Objective: Glomerulosclerosis is characterized by extracellular matrix accumulative and is often associated with mesangial cell proliferation. Curcumin showed a protective effect on anti-glomerular basement membrane (anti-GBM) nephritis in vivo, although their cellular localization and mechanism of action is still unclear. In this study, a glomerular mesangial cell line derived from fetus was used to determine whether curcumin could inhibit the cell proliferation and alter the extracellular matrix turnover.
Methods: The cell activity was determined with MTT method. Mesangial cells were cultured in vitro and incubated with 0, 3.125, 6.25, 12.5, 25, 50, 100 and 200 micromol/L curcumin. In addition,human mesangial cells were cultured with or without LPS (10 microg/ml) in presence or absence of various concentrations of curcumin (4, 16 and 200 micromol/L), respectively. The supernatant and cells were collected. Then, the levels of the collagen type IV and III protein in the supernatant were determined by using enzyme-linked immunosorbent assay and the IL-1 beta and MCP-1 mRNA in the cells was measured by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) after subconfluent quiescent mesangial cells were incubated with various concentrations of curcumin for 24 h in vitro.
Results: Curcumin at the concentration equal to or over 6.25 micro mol/L was able to inhibit the proliferation of mesangial cells in a dose-dependent manner, the optical density according to the sequential concentrations of curcumin was 0.65 +/- 0.02, 0.62 +/- 0.04, 0.56 +/- 0.01, 0.53 +/- 0.02, 0.51 +/- 0.03, 0.44 +/- 0.05, 0.41 +/- 0.07 and 0.38 +/- 0.06. Without any stimulation, human mesangial cells secreted some collagen type IV and III (10 +/- 9.13 ng/ml and 29.5 +/- 0.58 ng/ml, respectively) and expressed some MCP-1 mRNA, but did not express IL-1 beta mRNA. LPS increased the expression of collagen type IV and III in the culture medium of mesangial cells in vitro [(138.75 +/- 23.23) ng/ml and (38.25 +/- 5.38) ng/ml] and up-regulated the IL-1 beta and MCP-1 mRNA expression [(16.91 +/- 1.68)% and (76.6 +/- 6.59)%]. Yet curcumin could significantly decrease collagen type IV and III in the supernatant of cultured mesangial cells induced by LPS (20.5 +/- 1.00, P < 0.05 and 20.5 +/- 4.12 ng/ml, P < 0.05) and down-regulated the mRNA expression of IL-1 beta and MCP-1 in mesangial cells induced by LPS (P < 0.01).
Conclusion: Curcumin could inhibit the human mesangial cell proliferation and alter the extracellular matrix turnover, meanwhile it could down-regulate the IL-1 beta and MCP-1 mRNA expression induced by LPS, which may be valuable in decreasing the progression of glomerulosclerosis.