The TAC and MDA Values in Patients with Chronic Suppurative Otitis Media

The oxidative stress is linked to many chronic diseases.The aim of the study was to assess the oxidative stress in chronic suppurative otitis media. The prospective study included a group of 60 patients with different forms of chronic suppurative otitis media (CSOM), cholesteatoma recidivism and a control group of 30 healthy people. The total antioxidant capacity (TAC) and malondialdehyde (MDA) concentrations were determined in serum of thepatients. We noticed a significant lower mean of TAC levels (p< 0.001) in patients with chronic suppurative otitis media (CSOM) with and without cholesteatoma compared to the control group. The MDA had significantly higher mean values (p< 0.001) compared to the healthy group.The imbalance of antioxidant systems to oxidizing molecules plays an important role in the pathogenesis of CSOM with and without cholesteatoma.

The control group was representedby 30 healthy people, aged between 6 and 54 years old.
The patients were divided into 4 groups: group M represented healthy people, group C includes patients with CSOM with cholesteatoma, group R included patients diagnosed with cholesteatoma recidivism and group O represented patients with CSOM without chBlood samples for analysis were collected between 7 and 10 AM, after 12 h of fasting, into empty tubes and stored on ice at 4 o C The serum was afterwards separated from the cells by centrifugation (3000 rpm for 10 min).Serum samples were stored at -20 o C until they were used.All patients underwent surgical treatment.

Determination of TAC
The serum TAC levels were measured using the TAC Assay Kit from Sigma Aldrich, for research and manual use, according to the instructions. The antioxidant capacity was measured in Trolox equivalents.

Determination of MDA
The lipid peroxidation was determined by using the MDA Assay Kit from Sigma Aldrich for research and manual use, which is based on the reaction of MDA with the thiobarbituric acid to form a colorimetric product, proportional to the MDA concentration. We used the colorimetric method and we measured the absorbance at 532nm.
Statistical analysis was performed using the SPSSprogram version 18.0.

Results and discussions
The The MDA values in the patient group with CSOM with cholesteatoma ranged between 0.715 nmol/µland 1.150nmol/µL, in the patients with CSOM, was between 0.814 nmol/µL -0.973 nmol/µL and, in patients with cholesteatoma recidivism, values ranged between 0.875nmol/ µl and 1.1071nmol/µL as it can be seen in table 2.
MDA serum level was found to be significantly lowerin the control group compared to the levels observed in patients with CSOM with and without cholesteatoma (0.948, 0.891 (p = 0.01) vs. 0.625, p = 0.001). The mean level in patients with cholesteatoma recidivismwas slightly higher   .3). The measurement of TAC is used as an indicator of the system's capacity to counteract oxidative stress-induced injury in tissues and cells [8][9][10] and it measures the entire antioxidant capacity of a serum sample, not only that of a single antioxidant [11].
Our study showed statistically significant higher levelsof TAC in the healthy group compared to groups with CSOM with or without cholesteatoma, thus demonstrating the existence of an imbalance between oxidant-antioxidant systems. Vascular proliferation, leukocyte infiltration, epithelial thickening, local oedema was linked to the overproduction of oxidants and the tissue damage in the middle ear [12][13][14]. Some studies show a decrease in the level of oxidative stress by ventilation tube insertion that decrease the local inflammation [15,16].
There are only 2 studies inliterature that measure TAC values in the patients' serumand which highlight, as in our   [17,18]. Lipid peroxidation represents the degradation of lipids which appearsas a consequence of oxidative damage and is a very useful marker for highlighting theoxidative stress. The cell membrane has the role of barrier for free radicals. Free radicals must pass through this barrier to interact with intracellular components. Free radicals start lipid peroxidation by removing the hydrogen from alpha-methylene groups of fatty acids in the cell membrane. At the end of the interaction, polyunsaturated acids are subsequently hydrolysed into biological compounds. One of the most important compounds is MDA which reflects the lipid peroxidation magnitude [19][20][21].
In our study, the MDA levels in the patients group with CSOM with and without cholesteatoma and cholesteatoma recidivism were higher compared to the healthy group, which reflect an increased lipid peroxidation, a result similar to a 2015 study [22]. According to Holecek et al.,lipoperoxidation may be a marker of disease severity in otitis media,being involved in many other otorhinolaryngological diseases [23][24][25]. Increased MDA values determined in serum and in the middle ear mucosa were found in albino rabbits, with a correlation between results, thus reflecting the tissue damage caused by otitis [26][27][28].
Yariktas et al. observed that an increased level of free oxygen radicals may contribute to development of otitis media with effusion [29,30] and antioxidant vitamins can be added to the treatment. Cemek et al. found higher MDA serum values in children with acute tonsillitis and acute otitis media and lower values of antioxidant vitamins [31,32].

Conclusions
In our study, total antioxidant capacity and lipid peroxidation were evaluated in patients with CSOM with and without cholesteatoma. The serum values of all patients were compared to those of the healthy control group. TAC values weresignificantlylower in patients compared to the healthy group. The lowest values were recorded in those with cholesteatoma recidivism,which may ensue from a prolonged tissue damage caused by free radicals. The MDAlevels in the patient groups were significantly higher compared to the healthy group, which reflects an increased lipid peroxidation rate.