Exploring the role of curcumin, nanocurcumin, and a PPAR agonist in preventing paraquat-induced systemic inflammation and oxidative stress in rats.

Objectives: We investigated the effects of curcumin, nanocurcumin, and pioglitazone, a peroxisome proliferator-activated receptor gamma (PPARγ) activator, on the systemic inflammation and oxidative stress induced by inhaled paraquat (PQ).

Materials and methods: The experimental design included male Wistar rats divided into nine groups. Animals of the control group (Ctrl) were exposed to saline and those of other groups to 54 mg/m³ PQ aerosols 8 times on alternate days. PQ exposing groups were treated with saline (PQ group), curcumin (30 mg/kg, Cu), nanocurcumin (2 and 8 mg/kg, NC-L, and NC-H), pioglitazone (5 mg/kg, Pio), Pio+ Cu-L, Pio + NC-L, and dexamethasone (0.03 mg/kg, Dexa). Pio was administered intraperitoneally and other treating agents by gavage for 16 days during the PQ exposure period. Total and differential white blood cell (WBC) counts, malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), thiol, interleukin (IL)-10, and tumor necrosis factor-alpha (TNF-α) levels were measured.

Results: The inhalation of PQ increased total WBC, differential WBC, MDA, IL-10, and TNF-α blood levels. It also decreased blood levels of CAT, SOD, and thiol. The treatment groups (Cu, NC-L, NC-H, Pio+Cu, Pio+NC-L, Pio, and Dexa) ameliorated PQ-induced alterations. Furthermore, the improvements in most parameters in the Pio+Cu and NC-L-treated group were more significant than the results of the three substances individually.

Conclusion: The amelioration of systemic inflammation and oxidative stress caused by inhaled PQ by Cu, NC, and Pio were shown. Furthermore, the findings indicated a synergistic effect between Pio with Cu and NC, suggesting the involvement of PPARγ-mediated mechanisms in the effects of curcumin.