Overall 28 term newborns with hyperbiluribinemia were enrolled. The infants’ mean birth weight was 3028 ± 366 g and median gestational age was 39 (37–40) weeks. The mean total serum bilirubin concentration at admission was 17.08 ± 3.67 mg/dL. Before photerapy the native thiol (µmol/L), total thiol (µmol/L) and disulfide (µmol/L) of the patients with hyperbiluribinemia was found to be 344.1 ± 85.16, 391.69 ± 91.23, and 23.8 ± 14.26 µmol/L, respectively.
After photerapy, we evaluated the native thiol, total thiol and disulfide of the patients with hyperbiluribinemia 298.38 ± 47.11, 340.42 ± 51.46, and 21.02 ± 7.08 µmol/L, respectively (Table 1).
Table 1
Comparison of biochemical parameters before and after phototheraphy.
Parameters | Before photoheraphy (N = 30) | After phototheraphy (N = 30) | p |
Albumin (g/dL) | 3.45 ± 0.31 | 3.32 ± 0.31 | 0.056 |
Bilirubin (mg/dL) | 17.07 ± 3.66 | 9.67 ± 2.19 | < 0.001 |
Total protein (g/dL) | 4.95 ± 0.53 | 4.75 ± 0.51 | 0.059 |
Native thiol (µmol/L) | 344.12 ± 85.63 | 298.38 ± 47.11 | 0.021 |
Total thiol (µmol/L) | 391.69 ± 91.23 | 340.42 ± 51.46 | 0.010 |
Disulfide (µmol/L) | 23.78 ± 14.26 | 21.02 ± 7.08 | 0.261 |
Disulfide / Native thiol (%) | 7.41 ± 4.72 | 7.15 ± 2.55 | 0.787 |
Disulfide /Total thiol (%) | 6.18 ± 3.40 | 6.17 ± 1.88 | 0.990 |
Native thiol / Total thiol (%) | 87.63 ± 6.80 | 88.1 ± 5.06 | 0.752 |
TAS (mmol Trolox equiv./lt) | 2.31 ± 0.70 | 1.75 ± 0.38 | < 0.001 |
TOS (µmol H2O2 equiv./lt) | 43.86 ± 12.35 | 28.12 ± 9.99 | < 0.001 |
OSI (AU) | 1.96 ± 0.51 | 1.65 ± 0.59 | 0.049 |
TAS (total antioxidant status), TOS (total oxidative stress), OSI (oxidative stress index), AU (Absorbance Units) Paired Paired sample t-test values are expressed as mean ± SD |
When we examine the changes in biochemical parameters in newborns before and after phototherapy treatment, we found a decrease in bilirubin, TOS, TAS, OSI levels (p < 0.001, p < 0.001, p < 0.001, p = 0.049, respectively, Table 1). The level of albumin were low in the after phototherapy group, however, didn’t reach significance level (p = 0.056). Native thiol level was decreased after phototherapy (p = 0.021).
Before phototherapy positive correlation was determined between native and total thiol. Similarly, positive correletion was found between biluribin and TAS; TOS and TAS levels. However, correlation analysis revealed a negative correlation between OSI and biluribin; TAS and OSI levels (Table 2).
Table 2
Correlation of oxidative stress parameters and bilirubine before phototherapy
| Native Thiol (µmol/L) | Total Thiol (µmol/L) | Disulfide (µmol/L) | TAS | TOS | OSI | Bilirubin |
Native Thiol (µmol/L) Pearson Correlation Sig. (2 tailed) N | 1 28 | 0.950** < 0.001 28 | 0.036 0.853 28 | -0.146 0.460 28 | 0.072 0.714 28 | 0.284 0143 28 | 0.052 0.792 28 |
Total Thiol (µmol/L) Pearson Correlation Sig. (2 tailed) N | 0.950** < 0.001 28 | 1 28 | 0.347 0.065 28 | -0.177 0.368 28 | 0.078 0.695 28 | 0.315 0.102 28 | 0.092 0.642 28 |
Disulfide (µmol/L) Pearson Correlation Sig. (2 tailed) N | 0.036 0.853 28 | 0.347 0.065 28 | 1 28 | -0.128 0.515 28 | 0.031 0.874 28 | 0.159 0.420 28 | 0.135 0.493 28 |
TAS Pearson Correlation Sig. (2 tailed) N | -0.146 0.460 28 | -0.177 0.368 28 | -0.128 0.515 28 | 1 28 | 0.671** < 0.001 28 | -0.445* 0.018 28 | 0.676** < 0.001 28 |
TOS Pearson Correlation Sig. (2 tailed) N | 0.072 0.714 28 | 0.078 0.695 28 | 0.031 0.874 28 | 0.671** < 0.001 28 | 1 28 | 0.321 0.096 28 | 0.369 0.054 28 |
OSI Pearson Correlation Sig. (2 tailed) N | 0.284 0.143 28 | 0.315 0.102 28 | 0.159 0.420 28 | -0.445* 0.018 28 | 0.321 0.096 28 | 1 28 | -0.382* 0.045 28 |
Bilirubin Pearson Correlation Sig. (2 tailed) N | 0.052 0.792 28 | 0.092 0.642 28 | 0.135 0.493 28 | 0.676** < 0.001 28 | 0.369 0.054 28 | -0.382* 0.045 28 | 1 28 |
* ** correlation is significant at the 0.01 level (2-tailed) TAS: (mmol Trolox Eq/L), TOS: (µmol H2O2 Eq/L), OSI: (arbitrary unit) |
After photherapy, we indicated positive correlation between TOS and OSI; native and total thiol (Table 3).
Table 3
Correlation of oxidative stress parameters and bilirubine after phototherapy
| Native Thiol (µmol/L) | Total Thiol (µmol/L) | Disulfide(µmol/L) | TAS | TOS | OSI | Bilirubin |
Native Thiol (µmol/L) Pearson Correlation Sig. (2 tailed) N | 1 28 | 0.963** < 0.001 28 | 0.171 0.375 28 | -0.078 0.694 28 | 0.098 0.622 28 | 0.130 0.509 28 | 0.211 0.281 28 |
Total Thiol (µmol/L) Pearson Correlation Sig. (2 tailed) N | 0.963 < 0.001 28 | 1 28 | 0.432* 0.019 28 | -0.068 0.730 28 | 0.102 0.605 28 | 0.136 0.491 28 | 0.171 0.385 28 |
Disulfide ((µmol/L) Pearson Correlation Sig. (2 tailed) N | 0.171 0.375 28 | 0.432 0.019 28 | 1 28 | 0.011 0.957 28 | 0.046 0.815 28 | 0.060 0.760 28 | -0.082 0.680 28 |
TAS Pearson Correlation Sig. (2 tailed) N | -0.078 0.694 28 | -0.068 0.730 28 | 0.011 0.957 28 | 1 28 | 0.251 0.197 28 | -0.323 0.093 28 | 0.078 0.691 28 |
TOS Pearson Correlation Sig. (2 tailed) N | 0.098 0.622 28 | 0.102 0.605 28 | 0.046 0.815 28 | 0.251 0.197 28 | 1 28 | 0.818** < 0.001 28 | 0.116 0.556 28 |
OSI Pearson Correlation Sig. (2 tailed) N | 0.130 0.509 28 | 0.136 0.491 28 | 0.060 0.760 28 | -0.323 0.093 28 | 0.818** < 0.001 28 | 1 28 | 0.020 0.919 28 |
Bilirubin Pearson Correlation Sig. (2 tailed) N | 0.211 0.281 28 | 0.171 0.385 28 | -0.082 0.680 28 | 0.078 0.691 28 | 0.116 0.556 28 | 0.020 0.919 28 | 1 28 |
* correlation is significant < 0.05 level ** correlation is significant at the 0.01 level (2-tailed) TAS: (mmol Trolox Eq/L), TOS: (µmol H2O2 Eq/L), OSI: (arbitrary unit) |
The percentage of difference in bilirubin change and oxidative stress markers was calculated, and the relationship between them was examined by linear regression analysis. It was found to be significant in the linear regression analysis, in which the 14.7% change in the native thiol value and the 15.1% change in the total thiol value were explained depending on the change in the total bilirubin (R = 0.38 R2: 0.147 p = 0.044; R = 0.38 R2:0.151 p = 0.041 respectively). No correlation was found between the differences in changes in other oxidative stress parameters.