[Effects of leflunomide on podocytes exposed to high glucose condition and its mechanism]

To explore the protective effects of leflunomide (A771726) on the expression of podocalyxin, NF-κB and matrix metalloproteinase-9 (MMP-9) in podocytes exposed to high glucose environment and elucidate its mechanism.

Podocytes were cultured in high glucose. And the altered expressions of podocyte protein podocalyxin were detected by Western blotting at different timepoints. Then podocytes were divided into 4 groups of normal glucose control, leflunomide, high glucose and hypertonic control. The expression level of podocalyxin protein in each group was detected by Western blotting. And NF-κB p65 and phosphorylation of NF-κB p65 (P-NF-κBp65) in podocytes cultured in high glucose were detected at different timepoints. And then the podocytes were divided into 5 groups of normal glucose, mannitol, hypertonic control, high glucose, leflunomide and PDTC (NF-κB blocker). And the expressions of MMP-9 protein in these groups were also detected by Western blotting.

In the high glucose environment, the expression of podocalyxin declined instantly. Compared with the high-glucose group, the podocalyxin expression of the leflunomide group was significantly higher than the high glucose group (0.46 ± 0.04 vs 0.13 ± 0.03, P < 0.05). After 30-minute stimulation by high glucose, the activation of NF-κB started and the expression of P-NF-κBp65 protein increased. Such activities peaked at 60 minutes and reverted to a basic level after 6 hours. Compared with the high glucose group, the expressions of MMP-9 in PDTC and leflunomide groups were significantly lower than the high glucose group. And the differences were statistically significant (0.71 ± 0.01, 0.64 ± 0.03 vs 1.64 ± 0.03, both P < 0.05).

Leflunomide has protective effects on podocytes in high glucose. And its mechanism is possibly due to a lowered expression of MMP-9 through an inhibition of NF-κB activation.