(P13-025-20) ALA/LA Protect Against DN db/db mice Oxidative Stress and Fibrosis Through the ROS/p38/TGF-β1 Pathway

Objectives: Both oxidative stress (OS) and fibrosis play a significant role in the pathobiology of diabetic nephropathy (DN). Hence, we observed the effects of a-linolenic acids / linoleic acid (ALA/LA) on renal oxidative stress and tubule fibrosis on DN db/db mice and clarified its possible mechanisms in vivo.

Methods: db/db and db/m mice were divided into four groups, including normal control group(db/m mice), DN model group(DN db/db mice),  low-dose group (DN db/db mice intervened by 250mg/kg.d mixture of ALA and LA, with the ratio of  1:4), high-dose group (DN db/db mice intervened by500mg/kg.d ALA / LA, with the ratio of  1:4). The effect of ALA/LA on DN db/db mice analyzed by ELISA,  realtime PCR, Westen Blot and pathophysiology methods.

Results: Compared to the DN model group, after ALA/LA intervention, fasting plasma glucose, renal function, inflammation factors, the level of oxidative stress and the degree renal pathological morphology damage of db/db mice were lower in the intervention group(P< 0.05).The SOD, CAT, MDA level (nmol/mgprot) in intervention group was 11.97±1.95, 20.13±1.67, 0.81±0.12, and that in the model group was5.87±1.87, 12.37±1.50, 1.07±0.10. BUN, SCr, UA in intervention group was 19.21±6.16mmol/L, 30.86±5.37μmol/L, 230.14±56.44μmol/L; and that in the model group was 9.74±3.77mmol/L, 22.22±3.9μmol/L, 172.56±27.32μmol/L.Intervention of ALA/LA decreased the protein and mRNA expression of TGF-β1, p-p38 (p38), p-ERK (ERK) and COLⅣ in kidney of db/db mice (P< 0.05). The relative mRNA level of TGF-β1, p38, ERK and COLⅣ in the intervention group was 0.64±0.14, 2.71±0.15, 2.48±0.47, 4.37±0.71, while that in the model group was17.63±4.84, 127.43±4.84, 15.91±3.55, 32.05±4.13.The relative protein level of TGF-β1, p-p38, p-ERK and COL-Ⅳ in the intervention group was 0.42±0.07, 0.13±0.04, 0.35±0.04, and 0.46±0.03, while that in the model group was 0.74 ±0.05, 0.90±0.03, 0.98±0.02, 1.06±0.10.

Conclusions: ALA/LA(1:4, 250mg/kg/d) has good antioxidant capacity in vivo. It inhibited the transduction action of p38 and ERK, reduced the activity of TGF-β₁, COL-Ⅳand ameliorate kidney fibrosis of DN db/db mice. The study on ALA/LA might provide research evidence and possible clinical treatment for DN.

Funding Sources: This work was financially supported by the National Natural Science Foundation of China (No. 81372986).