In vivo/in silico insight into the effect of titanium dioxide nanoparticle on serum paraoxonase 1 activity in rat.

Serum paraoxonase1 (PON1) has special function in human body organism including the antioxidant and anti-atherogenic properties. In the present study, the effect of TiO2 nanoparticles on the activity and structure of the PON1 has been evaluated through in vivo and in silico methods. After treatments of the rats with different doses of TiO2 NPs, blood samples were collected and serum PON1 activity was measured by phenylacetate and paraoxon as substrate. In addition, the effects of TiO2 NP on enzyme structure were analyzed through Molecular dynamic (MD) simulation via Gromacs software package to obtain RMSD, RMSF, Rg, SASA, and secondary structures values. A significant reduction (p < 0.05) in arylesterase & paraoxonase activities of serum PON1 were monitored in Spectrometric assays when rats were treated with 150 and 200 mg/kg doses of TiO2 NPs. RMSD, RG, RMSF, and SASA values in the presence of TiO2 have been increased while RMSF values of the L1 and L2 loops (gate of the catalytic site) have been reduced. Moreover, Hydrogen bonds and secondary structure values of the enzyme decreased in the presence of TiO2 NP. All of these MD simulation results could indicate the instability of the PON1 structure bounded to TiO2 NP. TiO2 NP could cause a disturbance in the enzyme structure and function of PON1 based on the results. PON1 prevents oxidation of LDL and can delay atherosclerosis progression while in the presence of TiO2 NP these protective effects could be endangered.Communicated by Ramaswamy H. Sarma.

Effects of Pioglitazone On the Lipid Profile, Serum Antioxidant Capacity, and UCP1 Gene Expression in Mouse Brown Adipose Tissue.

BACKGROUND: Pioglitazone increases insulin sensitivity and improves glycemic control in type 2 diabetics. In this study, we evaluated the effects of pioglitazone on the uncoupling protein 1 (UCP1) expression in mouse brown adipose tissue (BAT), and on recovery from oxidative stress due to a high-fat diet. METHODS: 30 mice were divided into three groups: group 1 received a normal diet, group 2 received a high-fat diet, and group 3 received a high-fat diet plus 30 mg/kg pioglitazone. After treatment, the cholesterol, triglyceride, paraoxonase 1 (PON1), total serum antioxidant capacity (TAC), malondialdehyde (MDA), and specific activity of hepatic catalase were measured. BAT UCP1 expression was evaluated at both the mRNA and protein levels. RESULTS: The weights differed between the groups (p<0.05). Serum MDA was greater and TAC, liver catalase, and PON1 were less than in group 2 than in group 1 (p<0.05). In Serum MDA was less and catalase activity was greater in group 3 than in group 2 (p<0.05). UCP1 gene expression was less in group 2 than in group 1 (p<0.05) but greater than in group 3 (p<0.05). CONCLUSION: Pioglitazone may have a protective role in high-fat-diet-induced oxidative stress by increasing the antioxidant capacity. Moreover, it can induce weight loss by increasing UCP1 mRNA and protein expression.

Comparison of Pure Palm Olein Oil, Hydrogenated Oil-Containing Palm, and Canola on Serum Lipids and Lipid Oxidation Rate in Rats Fed with these Oils.

BACKGROUND: Due to increased consumption of canola oil and hydrogenated oil containing palm and palm olein, and their possible effects on serum lipoproteins, the present study was conducted to determine the effects of these oils on lipids and lipid oxidation level. METHODS: In this experimental study, 88 Wistar rats were randomly assigned to four groups. Control group (A) was on a normal diet. Groups B, C, and D, in addition to normal diet, were fed with hydrogenated oil-contained palm oil, pure palm olein oil, and canola oil, respectively for 4 weeks. Serum Biochemical factors [total cholesterol (TC), triglyceride (TG), LDL, HDL, LDL/HDL ratio, oxLDL, paraoxanase-1 (PON1), and malondialdehyde (MDA)] were measured. RESULTS: The lowest mean serum TC was seen in the control group and the highest in the group B. There were differences in TC, TG, HDL, MDA, and PON1 between the control group and other groups (P<0.001). The lowest and highest LDL/HDL ratios were observed in the group C and the control group, respectively. Significant differences were seen in OxLDL and PON1 between the control group and other three groups (P<0.05), while there were no significant differences in oxLDL and PON1 among the other three groups (P>0.05). MDA was higher in groups C and D. CONCLUSION: Canola oil, hydrogenated oil-containing palm and palm olein may increase atherosclerosis risk through decreasing PON1 activity and elevating oxLDL. Palm olein oils in rats' diets cause a considerable decrease in LDL and help to increase HDL.