Hematological results

The results of Hb, RBCs, Hct %, MCH, MCHC, MCV, WBCs, and platelet count (Plt) showed no statistical difference in their mean values following oral administration of quercetin or curcumin for 51 days as compared with the control group. Exposure of rats to whole-body gamma irradiation at fractionated doses (2 Gy, four times, every 3 days) up to 8 Gy triggered a highly significant statistical decrease in Hb, RBCs, MCH, MCHC, WBC count, and platelet count (P < 0.01) with a significant statistical decrease in the Hct %, MCV on the 14th day following irradiation process as compared to the control values (P < 0.05). The dual oral administration of both quercetin and curcumin pre-irradiation induced a highly significant increase in all studied parameters (P < 0.01) throughout the experimental times as compared with the corresponding irradiated group value. The co-administration of both quercetin and curcumin postirradiation showed a highly significant increase in the RBC count, WBCs, and platelet count on the 14th day (P < 0.01) as compared with the irradiated group values, indicating that administration of both quercetin and curcumin before exposure to gamma radiation was more effective than their postirradiation administration. All the hematological parameters are listed in Table 2 and illustrated in Fig. 1.

Table 2 Hematological parameters Hb, RBCs, Hct %, MCH, MCHC, MCV, WBCs, and Plt for the six rat groupsFig. 1

A graphical representation of the hematological parameters obtained from the different rat groups

Biochemical resultsPlasma thiobarbituric acid reactive substances (TBARS) concentration

The oral administration of Quer or Cur for consecutive 51 days showed no significant differences in plasma TBARS concentration as compared with the control untreated group. Exposure of rats to the fractionated doses of \(\gamma\)-irradiation at up to 8 Gy resulted in highly significant increases in the TBARS concentration (P < 0.01) as compared with the control values. Administration of both Quer and Cur before irradiation showed a significant decrease in the TBARS concentration (P < 0.05) as compared with the corresponding irradiated group, while their postirradiation administration showed a nonsignificant decrease (P > 0.05) as compared with the corresponding irradiated group, the recorded values are shown graphically in Fig. 2 and listed in Table 3.

Fig. 2

A graphical representation of the TBARS and GSH obtained of the different rat groups

Table 3 Biochemical parameters, TBARS and GSH recorded for the different rat groupsBlood glutathione (GSH) content

The oral administration of Quer or Cur for consecutive 51 days showed no significant differences in blood GSH content as compared with the control untreated group. Exposure of rats to the fractionated doses of \(\gamma\)-irradiation at up to 8 Gy resulted in a nonsignificant statistical decrease in the mean value of serum GSH level (P > 0.05) as compared with the control group. Administration of both Quer and Cur before irradiation induced a highly significant decrease in the GSH level (P < 0.01), while their postirradiation administration showed a significant statistical decrease in its level (P < 0.05) as compared with the corresponding irradiated group. The recorded values are displayed in Fig. 2 and Table 3.

Liver function results

As presented in Table 4, and depicted in Fig. 3, oral supplementation of Quer or Cur for consecutive 51 days did not cause a significant statistical difference in the serum ALT, AST, ALP activities, or serum total protein content as compared with the control group values. A significant statistical increase was noticed in ALT, AST, and ALP activities on the 14th day (P < 0.01) in the \(\upgamma\)-irradiated rat group with a significant decrease in the serum total protein values (P < 0.05) as compared with the control group values. Pre-irradiation administration of both Quer and Cur resulted in a significant decrease in serum ALT activity (P < 0.05) with a highly significant statistical increase (P < 0.01) in the total protein content, otherwise, there was a nonsignificant decrease in both AST and ALP activities (P > 0.05) as compared with the irradiated group recorded values. Oral administration of both Quer and Cur postirradiation resulted in a nonsignificant amelioration of the radiation-induced decrease of ALT, AST, and ALP activities values (P > 0.05) with an insignificant increase in the total protein content (P > 0.05) as compared with the corresponding irradiated group values.

Table 4 Liver function parameters recorded for the different rat groupsFig. 3

A graphical representation of the liver function parameters obtained from the different rat groups

Lipid profile results

No significant differences were detected in the serum total cholesterol, triglycerides, HDL, and LDL levels between the control group and the groups treated with quercetin or curcumin. The current experiment elucidated a highly significant elevation (P < 0.01) in the serum total cholesterol, triglycerides, HDL, and LDL concentrations following fractionated doses of γ-radiation as compared with those of the control rats. Pre-irradiation treatment of rats with both Quer and Cur induced a significant decrease in the cholesterol level (P < 0.05) with a highly significant decrease in both triglyceride and HDL levels (P < 0.01) and a nonsignificant decrease in the LDL level (P > 0.05) as compared with the irradiated group values, whereas, its postirradiation treatment exerted a nonsignificant decrease in the serum total cholesterol, triglycerides, and LDL (P > 0.05) levels with a significant decrease in the HDL level (P < 0.05) as compared with the irradiated group values (Table 5). A graphical illustration of the different lipid parameters recorded is shown in Fig. 4.

Table 5 Lipid profile parameters recorded for the different rat groupsFig. 4

A graphical representation of the lipid profile parameters obtained from the different rat groups

Histopathological results

Histological examination of a liver section of the control group revealed a normal histological appearance of the hepatocytes, which are polygonal in shape and radially disposed of in the liver lobule. Each hepatic cell has a centrally located nucleus with one or two prominent nuclei. Occasionally, the liver cells appear binucleated. The spaces between the hepatic plates contain the liver sinusoids with phagocytic cells of the mononuclear phagocyte series known as Kupffer cells. Each hepatic lobule has a central vein at its core (Fig. 5a). Liver sections of rats of the quercetin group showed the same normal histological appearance including a normal central vein, dilated portal vein, and bile duct. Hepatocytes appeared with central vesicular nuclei where some hepatocytes are double nucleated as a sign of regeneration. Kupffer cells appeared activated as seen in Fig. 5b. Curcumin-treated rats showed the same normal architecture of hepatic parenchymal cells with the blood sinusoids that appeared occupied by blood cells with activated Kupffer cells. The portal tract appeared normally formed of the portal vein and bile duct (Fig. 5c).

Fig. 5

Photomicrograph from the liver of rats showing: a The control group showing normal central vein (CV), cords of healthy hepatocytes with central vesicular nuclei radiating from it and separated from each other by blood sinusoids (S). Few cells have pyknotic nuclei (red arrows). b and c The Quer and Cur groups showed portal vein (PV) and normal bile duct (BD), healthy hepatocytes with central vesicular nuclei (black arrows), and some cells appeared binucleated (arrowheads) with activated Kupffer cells (yellow arrows). d Radiation (R) group showing dilated congested central vein (CV) with discontinuation (thick red arrow) and delamination (thick black arrow) of its lining, hepatocytes with degenerative changes as some with pyknotic nuclei (red arrow) and others with vacuolated cytoplasm (blue arrows). e Quer + Cur + R group showing normal portal vein (PV), hepatic artery (HA), bile duct (BD), and hepatocytes (black arrows) some with binucleated cells (arrowheads). f R + Quer + Cur group showing normal portal vein (PV), sinusoids, hepatocytes, some with prominent nucleolus (black arrows), and others with pyknotic nuclei (red arrow) and activated Kupffer cells (yellow arrows). Scale bar: 30 µm

Whole-body exposure of rats of the current experiment to 8 Gy gamma irradiation delivered as a fractionated dose (2 Gy every 3 days) showed loss of the normal hepatic architectures with dilated central vein with corrugated walls and widened blood sinusoids. Some hepatocytes appeared degenerated with pyknotic nuclei and vacuolated cytoplasm (Fig. 5d).

Administration of both quercetin and curcumin before gamma radiation exposure showed more or less normal hepatic architecture with the normal portal vein and bile duct. Hepatocytes appeared healthy with central vesicular nuclei, some of which appeared binucleated as a sign of regeneration as depicted in (Fig. 5e). Administration of both quercetin and curcumin following gamma radiation exposure showed signs of recovery and tissue repair indicated by the well-developed hepatic architecture with a normal portal tract formed of the portal vein and bile duct, and widened blood sinusoids were still detected. Most of the hepatocytes appeared with central vesicular nuclei, while others have pyknotic nuclei (Fig. 5f).

FTIR spectroscopy

The average FTIR spectra of control liver tissues in 4000–400 cm−1 regions is shown in Fig. 6. The main bands are labeled in the figure, and the band assignments are given in Table 6, (Stuart 1997; Haris and Severcan 1999; Movasaghi et al. 2008; Bozkurt et al. 2010; Severcan et al. 2010; Cakmak et al. 2011).

Fig. 6

The average FTIR spectra of control liver tissues in the 4000–400 cm−1 region

Table 6 Band assignments of major transmissions in IR spectra of control liver tissue in 4000–400 cm−1 regions

The average FTIR spectra of control, Quer, Cur, irradiated and combined Quer-Cur before and after irradiation-treated rat liver tissues in 4000–400 cm−1 region is shown in Fig. 7. The figure reveals prominent differences between the average spectra belonging to the different groups. Subtle changes in a band shape, band position, and band intensity of vibrational bands represent changes in biomolecule concentration, composition, and structure. It was observed that the broad peak of the OH group, CH2, C=O, amide I, and C=C, respectively, had increased in intensity by varying the dopant material. All peaks before 1600 cm−1 decreased in intensity by varying dopants. Peaks after 1600 cm−1 increased in intensity by adding quercetin and decreased by adding curcumin. By adding quercetin, the peak positions were shifted to a lower wavenumber, while by adding curcumin, there were some fluctuations (many peaks increase in wavenumber and the others decrease). The reduced wavenumber may be due to the dopant material not interacting properly with the liver’s protein. The contrary is true; the increase in wavenumber is caused by the strong interaction between proteins and dopant material through the formation of hydrogen bonds.

Fig. 7

The average FTIR spectra of control, quercetin, curcumin, irradiated, and combined quercetin–curcumin before and after irradiation-treated liver tissues in 4000–400 cm−1 region

The radiation effect on liver tissues was indicated by the shift of 3289 cm−1 of NH stretching protein amide A to a higher intensity concerning the control and the disappearance of the OH stretching. It also shows a high decrease of the peaks 1745, 1651, 1539, and 1461 cm−1 of phospholipids, amide 1 and amide 2 and lipid–protein, respectively, to a lower intensity concerning the control. There is also a shift in the peaks of 3006 cm−1 for olefinic CH stretching for lipid and cholesterol, 2924 cm−1 CH2 for antisymmetric lipids, and a peak of 2854 cm−1 for CH2 symmetric lipids to lower intensity indicating the direct effect of radiation on liver tissues. It is shown from the figure that the radiation effect of the post-treated quercetin–curcumin group showed a decrease in the intensity of all peaks indicating its effect against radiation effect. There was a higher shift to higher intensity values for the irradiated pretreated quercetin–curcumin group in a close match with the control group. The combined doping of both quercetin and curcumin before and after irradiation showed a more significant effect in ameliorating the radiation effect on liver tissues, nearly restoring all the peaks to the control of the unirradiated one.