[Effect of high glucose on PKC and MMPs/TIMPs in human mesangial cells].
OBJECTIVE
To explore the relationship between protein kinase C (PKC) and matrix metalloproteinase (MMPs)/tissue inhibitor of metalloproteinase (TIMPs) in human mesangial cells under the high glucose medium, and to analyze the effect of PKC and MMPs/TIMPs in diabetes nephropathy (DN).


METHODS
Normal human mesangial cells (NHMC) were divided into 4 groups: a control group(N, 5 mmol/L glucose), a high glucose group (H, 30 mmol/L glucose), a PKC inhibition group (P, 30 mmol/L glucose plus 10-5 mol/L chelerythrine chloride), and an mannitol group (M, 5 mmol/L glucose plus 25 mmol/L mannitol). Cell proliferation was measured by MTT at 24,48 or 72 hours. The activity of PKC was measured by ELISA and the mRNA and protein expressions of MMP2, 9 and TIMP1, 2 were examined by RT-PCR and Western blot.


RESULTS
High glucose increased the activity of PKC as well as the expressions of mRNA and protein of MMP2, 9 and TIMP1, 2.The ratio of MMP-2/TIMP-2 and MMP-9/TIMP-1 was significantly decreased in the high glucose group compared with that of the control group (P<0.05). The mRNA and protein expressions of MMP2, 9 and TIMP1 were significantly increased in the PKC inhibition group compared with the control group (P<0.01). The ratio of MMP-2/TIMP-2 and MMP-9/TIMP-1 increased in the inhibition group compared with that of the high glucose group (P<0.05 or P<0.01). The activity of PKC was negatively correlated with the protein ratio of MMP-2/TIMP-2 and MMP-9/TIMP-1(rý-0.651,rý-0.702, both P<0.05).


CONCLUSIONS
High glucose can activate PKC in mesangial cells. The activity of PKC influences the expression of MMPs/TIMPs in the progressing of DN.
Yang
Jinghua
J
Department of Nephrology, Xiangya Hospital, Central South University, Changsha 410008, China.
Zhou
Qiaoling
Q
Wang
Yanhui
Y
Liu
Kanghan
K
Zhang
Jun
J
D002478:Cells, Cultured; D005947:Glucose / Q000009:adverse effects* / Q000494:pharmacology; D006801:Humans; D006943:Hyperglycemia / Q000378:metabolism; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D050527:Mesangial Cells / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism*; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000378:metabolism
D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D019715:Tissue Inhibitor of Metalloproteinase-1; D019716:Tissue Inhibitor of Metalloproteinase-2; D011493:Protein Kinase C; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9; D005947:Glucose