Cell experiment:

ARPE-19 cells are cultured under normoglycemic (5.5 mM D-glucose) or hyperglycemic (25 mM D-glucose) conditions for 18 days at 37℃ under 5% (v/v) CO2 in medium DMEM/F12 supplemented with 10% (v/v) fetal serum (FS) and penicillin/streptomycin. ARPE-19 cells are used and the media is changed every 3-4 days. The conditions tested are: (1) Control cells which are maintained in 5.5 mM D-glucose (normal glucose) for 18 days. (2) Cells cultured in 5.5 mM D-glucose treated with 100 μM Fenofibric acid for 72 h (days 16, 17, and 18; 1 application/day). (3) Cells cultured as in (1) or (2) and submitted to hypoxia (1% oxygen) for the last 6 or 24 h. (4) Cells maintained in 25 mM D-glucose (HG) for 18 days. (5) Cells cultured in 25 mM D-glucose treated with 100 μM Fenofibric acid for 72 h (days 16, 17, and 18; 1 application/day). (6)Cells cultured as in (4) or (5) and submitted to hypoxia (1% oxygen) for the last 6 or 24 h[4].

Animal experiment:

The anti-inflammatory activity of fenofibrate and its active metabolite fenofibric acid is assessed by injecting 0.1 mL of 1% carrageenan solution prepared in saline (sub-plantar) to the right hind paw of the rats. Rats are divided into 6 groups of six animals each. The first group serves as negative control and receives 1% tween-80 in distilled water, 10 mL/kg body mass. Group 2 and 3 receive a single dose of fenofibrate and standard drug diclofenac at 10 mg/kg body mass, whereas groups 4, 5, and 6 receive 3 doses of Fenofibric acid at 1, 5, and 10 mg/kg body mass, respectively. All the drugs are given orally using gavages 60 min before the injection of 0.1 mL of 1% carrageenan through sub-plantar route. The volume of oedema of test and control groups is measured using plethysmometer at 0, 1, 2, and 3 h after induction of inflammation[2].

Fenofibric acid, an active metabolite of fenofibrate, is a PPAR activitor, with EC50s of 22.4 μM, 1.47 μM, and 1.06 μM for PPARα, PPARγ and PPARδ, respectively; Fenofibric acid also inhibits COX-2 enzyme activity, with an IC50 of 48 nM.

Fenofibric acid is a PPAR activitor, with EC50s of 22.4 μM, 1.47 μM, and 1.06 μM for PPARα, PPARγ and PPARδ, respectively[1]. Fenofibric acid (10, 25, 50, 75, and 100 nM) dose-dependently inhibits COX-2 enzyme, with IC50 of 48 nM[2]. Fenofibric acid (500 nM) reduces abundance of AOX1 protein in HepG2 cells[3]. Fenofibric acid (100 μM) decreases JNK1/2, c-Jun, and p38 MAPK phosphorylation, and prevents the accumulation of reactive oxygen species, endoplasmic reticulum (ER) stress and disruption of blood retinal barrier (BRB) in response to the combination of high-glucose (HG) and hypoxia in ARPE-19 cells. Fenofibric acid (100 μM) activates IGF-IR/Akt/ERK1/2-mediated survival signaling pathways in ARPE-19 cells under HG conditions and hypoxia[4].

Fenofibric acid (1, 5, 10 mg/kg, p.o.) shows anti-inflammatory activity in Wistar rats with acute inflammation induced by carrageenan[2].

References:
[1]. Dietz M, et al. Comparative molecular profiling of the PPARα/γ activator aleglitazar: PPAR selectivity, activity and interaction with cofactors. ChemMedChem. 2012 Jun;7(6):1101-11.
[2]. Prasad GS, et al. Anti-inflammatory activity of anti-hyperlipidemic drug, fenofibrate, and its phase-I metabolite fenofibric acid: in silico, in vitro, and in vivo studies. Inflammopharmacology. 2017 Dec 13.
[3]. Neumeier M, et al. Aldehyde oxidase 1 is highly abundant in hepatic steatosis and is downregulated by adiponectin and fenofibric acid in hepatocytes in vitro. Biochem Biophys Res Commun. 2006 Nov 24;350(3):731-5. Epub 2006 Sep 27.
[4]. Miranda S, et al. Beneficial effects of fenofibrate in retinal pigment epithelium by the modulation of stress and survival signaling under diabetic conditions. J Cell Physiol. 2012 Jun;227(6):2352-62.