Total Antioxidant Status (TAS)



Laparoscopic cholecystectomy is the gold standard for the treatment of gallstone disease; however, adverse hemodynamic changes induced by increased intra-abdominal pressure due to pneumoperitoneum are known to occur. In this paper, we investigate the effects of pneumoperitoneum on oxidative stress markers, including paraoxonase, arylesterase, total oxidant status, and total antioxidant status, during laparoscopic cholecystectomy.

Patients And Methods:

Patients who underwent laparoscopic cholecystectomy were classified as Group I, while patients who underwent surgical procedures for an abdominal wall hernia under general anaesthesia were classified as Group II. Blood samples were obtained during the preoperative period, the perioperative period, and 24 hours after surgery (postoperative day 1). Leukocyte counts, neutrophil rates, paraoxonase activities, arylesterase activities, and levels of total oxidant and antioxidant status were measured.

Materials And Methods

This study was conducted at Konya Numune State Hospital. Group, I patients underwent an LC procedure, while group II patients underwent surgical procedures to treat hernias of the abdominal wall under general anaesthesia. The presence of any of the following conditions was used as exclusion criteria in this study: diabetes mellitus, neoplastic disease, inflammatory disease (such as infections and autoimmune disorders), hypercholesterolemia, hypertriglyceridaemia, use of an antihypertensive drug, use of lipid-lowering drugs. , use of antioxidants, known secondary hypertension, chronic kidney failure, cerebrovascular disease, ischemic heart disease, congestive heart failure, gastrointestinal disease, or liver disease.

The study protocol was approved by the Ethics Committee of the Meram School of Medicine, Selcuk University, and was carried out in accordance with the Declaration of Helsinki, Good Clinical Practice Guidelines. Participants were informed of the nature of the study and informed consents were obtained.

Blood samples were obtained preoperatively, perioperatively, and 24 hours after surgery (postoperative day 1). Serum samples were centrifuged for 15 min at 3000 rpm, transferred to Eppendorf tubes and stored at -80 ° C. Samples were used to measure paraoxonase, TOS and TAS activity.

  • Measurement of paraoxonase and arylesterase activities.

Paraoxonase and arylesterase activities were measured using paraoxon and phenylacetate as substrates, respectively. The basal activity of paraoxonase was measured. The rate of hydrolysis of paraoxon (diethyl-p-nitrophenyl phosphate) was measured by monitoring an increase in absorbance at 412 nm at 37 ° C in an autoanalyzer (Beckman Coulter, Fullerton, CA, USA). The amount of p-nitrophenol generated was calculated from the molar absorptivity coefficient at pH 8.5, which was 18290 M – 1cm – 1. The activity of paraoxonase is expressed as U / L of serum. Phenylacetate was used as a substrate to measure arylesterase activity. One unit of arylesterase activity was defined as 1 μmol of phenol generated per minute and is expressed as U / L of serum.

  • Measurement of total antioxidant status

Serum TAS levels were determined using an automated measurement method based on bleaching the characteristic colour of a radical cation plus s 2,2′-casino-bis [3-ethylbenz-thiazoline-6-sulfonic (ABTS)] caused by antioxidants. The results are expressed in mmol of Trolox / L equivalents.

  • Measurement of the total oxidation state

The TOS levels of the sera were determined using a new automated measurement method. The oxidants present in the sample oxidize the ferrous ion-o-dianisidine complexes to ferric ions. The oxidation reaction is enhanced by glycerol molecules that are abundantly present in the reaction medium. Ferric ions form a coloured complex with orange xylenol in an acid medium. Therefore, the intensity of the colour, measured spectrophotometrically, is related to the total number of oxidant molecules present in the sample. The assay is calibrated with hydrogen peroxide and results are expressed in terms of micromolar hydrogen peroxide equivalent per litre (μmol H2O2 equiv./L).

  • Statistic analysis

Statistical analysis was performed with SPSS software for Windows, version 13.0. Results are expressed as mean ± standard deviation (SD). Statistical analysis was performed using the Mann-Whitney U test and the paired t-test. Statistical significance was assumed at a level of P <0.05.


Differences in leukocyte counts and neutrophil rates were not significant between the two groups. In Group I, no significant differences was identified in the levels of total oxidant and antioxidant status; however, paraoxonase and arylesterase levels were lower on postoperative day 1. No significant changes in total oxidant state, total antioxidant status, and paraoxonase or arylesterase activities were observed in Group II. Total perioperative antioxidant status and arylesterase level were higher in Group I compared to Group II.


Paraoxonase and arylesterase levels are useful markers in evaluating oxidative stress caused by intra-abdominal pressure from pneumoperitoneum.


Laparoscopy, Cholecystectomy, Paraoxonase, Arylesterase, Oxidative markers.

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