Biochemically and histopathologically comparative review of thiamine's and thiamine pyrophosphate's oxidative stress effects generated with methotrexate in rat liver

Abstract

Background: Oxidative liver injury occurring with methotrexate restricts its use in the desired dose. Therefore, whether or not thiamine and thiamine pyrophosphate, whose antioxidant activity is known, have protective effects on oxidative liver injury generated with methotrexate was comparatively researched in rats using biochemical and histopathological approaches.

Material/methods: Thiamine pyrophosphate+methotrexate, thiamine+methotrexate, and methotrexate were injected intraperitoneally in rats for 7 days. After this period, all animals' livers were excised, killing them with high-dose anesthesia, and histopathologic and biochemical investigations were made.

Result: Biochemical results demonstrated a significant elevation in level of oxidant parameters such as MDA and MPO, and a reduction in antioxidant parameters such as GSH and SOD in the liver tissue of the methotrexate group. Also, the quantity of 8-OHdG/dG, a DNA injury product, was higher in the methotrexate group with high oxidant levels and low antioxidant levels, and the quantity of 8-OHdG/dG was in the thiamine pyrophosphate group with low oxidant levels and high antioxidant levels. In the thiamine and control groups, the 8-OHdG/dG rate was 1.48 ± 0.35 pmol/L (P>0.05) and 0.55 ± 0.1 pmol/L (P<0.0001). Thiamine pyrophosphate significantly decreased blood AST, ALT and LDH, but methotrexate and thiamine did not decrease the blood levels of AST, ALT and LDH. Histopathologically, although centrilobular necrosis, apoptotic bodies and inflammation were monitored in the methotrexate group, the findings in the thiamine pyrophosphate group were almost the same as in the control group.

Conclusions: Thiamine pyrophosphate was found to be effective in methotrexate hepatotoxicity, but thiamine was ineffective.

Figure 1

The AST activities in methotrexate, control, TPP (thiamine pyrophosphate) + methotrexate and thiamine + methotrexate rat groups. Results are the means ± Standart error of the mean.

Figure 2

The ALT activities in methotrexate, control, TPP (thiamine pyrophosphate) +methotrexate and thiamine + methotrexate rat groups. Results are the means ± Standart error of the mean.

Figure 3

The LDH activities in methotrexate, control, TPP (thiamine pyrophosphate) + methotrexate and thiamine + methotrexate rat groups. Results are the means ± Standart error of the mean.

Figure 4

Normal hepatic histology belonging to the control group.

Figure 5

(A) The histopathological examination of the liver tissue of Thiamine pyrophosphate + methotrexate group. A histopathologic appearance close to normal is present, and no apoptotic bodies, necrosis, inflammation and dilatation in the central vein are monitored. (B) The histopathological examination of the liver tissue of Thiamine pyrophosphate + methotrexate group. A histopathologic appearance close to normal is present, and no apoptotic bodies, necrosis, inflammation and dilatation in the central vein are monitored.

Figure 6

(A) The histopathological examination of the liver tissue of methotrexate group. Focal necrosis (star), dilatation in the central vein (arrow) accompanied also by inflammatory cells were monitored in the methotrexate group. (B) The histopathological examination of the liver tissue of methotrexate group. Apoptotic bodies with condensed cytoplasm and with peripheralized and pyknotic nuclei.

Figure 7

(A) The histopathological examination of the liver tissue of Thiamine + methotrexate group. (B) The histopathological examination of the liver tissue of Thiamine + methotrexate group. In the group given thiamine apoptotic bodies and focal necrosis are monitored in the interstitial area.