Fig 1.
Oleic acid administration improves survival and ameliorates clinical score in septic mice.
Animals were treated with oleic acid for 14 days. On the 15th day, mice were subjected to CLP, and (A) 6 and (B) 24 hours after surgery, the clinical score was evaluated as described in the Materials and Methods. (C) The survival rate was assessed for 7 days after CLP. Control groups received saline. Each group consisted of 15 to 23 animals (clinical score at 6 hours: sham = 15 animals, sham + OA = 18 animals and CLP and CLP + OA = 23 animal; at 24 hours: sham and sham + OA = 18 animals, CLP = 18 animals, CLP + OA = 22 animals) in 3 independent experiments. For survival rates, 10 animals from each group were analyzed. This is a representative curve from 3 independent experiments. p < 0.05 * CLP vs sham, # CLP vs CLP plus oleic acid; log-rank test for mortality and one-way ANOVA followed by Newman-Keuls test for the clinical score.
Fig 2.
Oleic acid administration does not affect food intake and body weight of mice.
(A) After 14 days of oleic acid administration, we estimated the food intake per body weight per cage. (B) Animals were followed for 14 days after OA administration and weighed on days 1, 7 and 14. Controls received the same volume of saline. Values represent the mean ± SEM from at least 13 animals.
Fig 3.
Oleic acid treatment ameliorates renal and hepatic functions in mice subjected to CLP.
Animals were treated with oleic acid for 14 days. On the 15th day, mice were subjected to CLP, and 24 hours after surgery, serum was collected for the quantification of (A) creatinine, (B) glutamic-oxaloacetic aminotransferase and (C) alanine aminotransferase. Each bar represents the mean ± SEM from 5–13 animals per group. p < 0.05 * CLP vs sham, + CLP vs sham plus OA, # CLP vs CLP plus oleic acid.
Fig 4.
Plasma NEFA concentrations are reduced after oleic acid treatment in septic animals.
Mice were treated for 14 days with oleic acid. On the 15th day, mice were subjected to CLP. Twenty-four hours after CLP, blood was collected for albumin quantification. (A)Total NEFA concentration (sum of average concentrations of the five NEFA) 24 hours after CLP in OA-treated and untreated animals. (B) Plasma concentrations of palmitoleic, linoleic, palmitic, oleic and stearic acids. (C) Plasma albumin levels. (D) Ratio of serum NEFA and albumin. Values represent the mean ± SEM of at least 5 animals. (Total NEFA and single fatty acid: sham = 7 animals, sham + OA = 5 animals, CLP = 6 animals and CLP + OA = 8 animals; Albumin and ratio of serum NEFA and albumin: sham = 5 animals, sham + OA = 6 animals, CLP = 5 animals and CLP + OA = 6 animals). The results are representative of 3 independent experiments. p < 0.05 * CLP vs sham, # CLP vs CLP plus oleic acid.
Fig 5.
Oleic acid increases the transcription of the CPT1A gene in septic mice.
Swiss mice were treated for 14 days with oleic acid. On the 15th day, mice were subjected to CLP. The liver was removed 24 hours after CLP. CPT1A mRNA was detected by RT-PCR. A representative gel of (A) CPT1A and of the (B) control GAPDH gene transcription. The loading control was GAPDH. (C)The bands were analyzed by densitometry and are represented as the CPT1A/GAPDH ratio. Values represent mean and SEM from 5–6 animals per group.
Fig 6.
Oleic acid treatment decreases MDA formation, and induces UCP2 and AMPK in septic mice.
Mice were treated for 14 days with oleic acid, and on the 15th day, CLP was performed. The liver was removed 24 hours after CLP for analysis of (A) MDA and (B) UCP2 by western blotting. The graph shows the densitometric analysis of the UCP2, AMPK and β-actin bands, as described in the methods. The results are expressed as the mean ± SEM of 5–6 animals. (* and +) p < 0.05 compared to sham and sham + OA (respectively) and (#) compared to CLP.
Fig 7.
OA alters fatty acid metabolism and organ dysfunction and improves sepsis outcome.
CPT1A –carnitine palmitoyltransferase 1A; PPAR–peroxisome proliferator-activated receptor, UCP2 –uncoupling protein 2; AMPK—5' AMP-activated protein kinase. OA activates AMPK, increases CPT1A and UCP2 and decreases fatty acid synthesis, resulting in an increase in oxidative processes. PPAR activation leads to an increase in the expression of CPT1A and UCP2; consequently, the fatty acid oxidation will be enhanced. Augmented fatty acid oxidation leads to a decrease in the NEFA plasma levels. Decreased NEFA and ROS levels would improve organ dysfunction and increase survival rate.