Protective role of quercetin against manganese-induced injury in the liver, kidney, and lung; and hematological parameters in acute and subchronic rat models

Abstract

Manganese (Mn) is an important mineral element required in trace amounts for development of the human body, while over- or chronic-exposure can cause serious organ toxicity. The current study was designed to evaluate the protective role of quercetin (Qct) against Mn-induced toxicity in the liver, kidney, lung, and hematological parameters in acute and subchronic rat models. Male Sprague Dawley rats were divided into control, Mn (100 mg/kg for acute model and 15 mg/kg for subchronic model), and Mn + Qct (25 and 50 mg/kg) groups in both acute and subchronic models. Our result revealed that Mn + Qct groups effectively reduced Mn-induced ALT, AST, and creatinine levels. However, Mn + Qct groups had effectively reversed Mn-induced alteration of complete blood count, including red blood cells, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, platelets, and white blood cells. Meanwhile, the Mn + Qct groups had significantly decreased neutrophil and eosinophil and increased lymphocyte levels relative to the Mn group. Additionally, Mn + Qct groups showed a beneficial effect against Mn-induced macrophages and neutrophils. Our result demonstrated that Mn + Qct groups exhibited protective effects on Mn-induced alteration of GRP78, CHOP, and caspase-3 activities. Furthermore, histopathological observation showed that Mn + Qct groups effectively counteracted Mn-induced morphological change in the liver, kidney, and lung. Moreover, immunohistochemically Mn + Qct groups had significantly attenuated Mn-induced 8-oxo-2'-deoxyguanosine immunoreactivity. Our study suggests that Qct could be a substantially promising organ-protective agent against toxic Mn effects and perhaps against other toxic metal chemicals or drugs.

Keywords: hematological parameters; kidney; liver; lung; manganese; quercetin.

Figure 1

Effect of Qct on blood ALT, AST, and creatinine in acute treatment. Notes: (A) Blood ALT level; (B) blood AST level; (C) blood creatinine level. Values presented as means ± SD (n=6). ^##P<0.001 versus control group; *P<0.01, **P<0.001 versus Mn group. Abbreviations: Mn, manganese; Qct, quercetin.

Figure 2

Effect of Qct on blood ALT, AST, and creatinine in subchronic treatment. Notes: (A) Blood ALT level; (B) blood AST level; (C) blood creatinine level. Values presented as means ± SD (n=6). ^##P<0.001 versus control group; *P<0.01, **P<0.001 versus Mn group. Abbreviations: Mn, manganese; Qct, quercetin.

Figure 3

Effect of Qct on lymphocytes, neutrophils, and eosinophils in acute treatment. Notes: (A) Neutrophil levels; (B) lymphocyte levels; (C) eosinophil levels. Values presented as means ± SD (n=6). ^##P<0.001 versus control group; *P<0.01, **P<0.001 versus Mn group. Abbreviations: Mn, manganese; Qct, quercetin.

Figure 4

Effect of Qct on lymphocytes, neutrophils, and eosinophils in subchronic treatment. Notes: (A) Neutrophil levels; (B) lymphocyte levels; (C) eosinophil levels. Values presented as means ± SD (n=6). ^##P<0.001 versus control group; *P<0.01, **P<0.001 versus Mn group. Abbreviations: Mn, manganese; Qct, quercetin.

Figure 5

Microscopic observations of the beneficial effect of Qct on blood macrophages and neutrophils in acute Mn-treated rat model. Abbreviations: Mn, manganese; Qct, quercetin.

Figure 6

Microscopic observation of the beneficial effect of Qct on blood macrophages and neutrophils in subchronic Mn-treated rat model. Abbreviations: Mn, manganese; Qct, quercetin.

Figure 7

Western blot analysis of effect of Qct on Mn-induced endoplasmic reticulum stress and stress-mediated apoptosis markers in acute rat model. Notes: (A) Expression of GRP78, CHOP, and caspase-3 proteins in the liver, kidney and lung in different treatment groups; (B) normalization of protein expression by relative density analysis of GRP78, CHOP, and caspase-3. Relative density expressed as ratios (GRP78, CHOP, and caspase-3/β-actin). ^##P<0.001 versus control group; *P<0.01, **P<0.001 versus Mn group. Abbreviations: Mn, manganese; Qct, quercetin.

Figure 8

Western blot analysis of effect of Qct on Mn-induced endoplasmic reticulum stress and stress-mediated apoptosis markers in subchronic rat model. Notes: (A) Expression of GRP78, CHOP, and caspase-3 proteins in the liver, kidney, and lung in different treatment groups; (B) normalization of protein expression by relative density analysis of GRP78, CHOP, and caspase-3. Relative density expressed as ratios (GRP78, CHOP, and caspase-3/β-actin). ^##P<0.001 versus control group; *P<0.01, **P<0.001 versus Mn group. Abbreviations: Mn, manganese; Qct, quercetin.

Figure 9

Histopathological images showing beneficial effect of Qct against Mn-induced damage in liver, kidney, and lung in acute model. Notes: Hepatic histopathology revealed that Mn treatment led to morphological alteration of hepatic features (arrow indicates zonal necrosis around central vein) compared to control group, while Mn + Qct groups showed an improvement tissue, with mild necrotic changes. Renal histopathology revealed that control Mn treatment led to morphological alteration of renal features (arrows indicate glomerular injury) compared with control group, while Mn + Qct groups exhibited protection of tissue, with mild glomerular injury. Pulmonary lung histopathology revealed that Mn treatment led to morphological alteration of lung features (arrow indicates granulomatous aggregation around bronchiole) while Mn + Qct groups exhibited protection of tissue with mild granulomatous aggregation around bronchioles. Abbreviations: Mn, manganese; Qct, quercetin.

Figure 10

Histopathological images showing beneficial effect of Qct against Mn-induced damage in liver, kidney, and lung in subchronic model. Notes: Hepatic histopathology revealed that Mn treatment led to morphological alteration of hepatic features (arrow indicates zonal necrosis around central vein) compared to control group, while Mn + Qct groups showed an improvement in tissue, with mild necrotic changes. Renal histopathology revealed that control Mn treatment led to morphological alteration of renal features (arrows indicate glomerular injury) compared with control group, while Mn + Qct groups exhibited protection of tissue, with mild glomerular injury. Pulmonary lung histopathology revealed that Mn treatment led to morphological alteration of lung features (arrow indicates granulomatous aggregation around bronchiole), while Mn + Qct groups exhibited protection of tissue, with mild granulomatous aggregation around bronchioles. Abbreviations: Mn, manganese; Qct, quercetin.

Figure 11

Immunohistochemical observation of the beneficial effect of Qct against Mn-induced oxidative marker 8-OHdG in acute model. Notes: Qct treatment showed protective effect of Qct on Mn-induced oxidative stress compared to control group. The Mn group exhibited 8-OHdG immunoreactivity relative to control group, while Mn + Qct groups attenuated 8-OHdG immunoreactivity. Abbreviations: Mn, manganese; Qct, quercetin.

Figure 12

Immunohistochemical observation of beneficial effect of Qct against Mn-induced oxidative marker 8-OHdG in subchronic model. Notes: Qct treatment showed protective effect of Qct on Mn-induced oxidative stress compared to control group. The Mn group exhibited 8-OHdG immunoreactivity relative to control group, while Mn + Qct groups attenuated 8-OHdG immunoreactivity. Abbreviations: Mn, manganese; Qct, quercetin.

Figure 13

The proposed mechanism of the protective role of Qct against Mn-induced tissue (liver, kidney, and lung) injury. Notes: High acute dose or chronic exposure of Mn causes alteration of biochemical and hematological parameters, including AST, ALT, creatinine, and CBC, which leads to induction of neutrophil and macrophage activities, followed by oxidative stress (8-OHdG). Oxidative stress leads to ER stress and ER stress-mediated apoptosis proteins (GRP78, CHOP, and caspase-3), resulting in tissue (liver, kidney, and lung) injury. Qct effectively attenuates Mn-induced organ (liver, kidney, and lung) injury through regulation of biochemical and hematological parameters (ALT, AST, creatinine, and CBC), followed by reduction of oxidative damage, ER stress, and ER stress-mediated apoptosis. Abbreviations: CBC, complete blood count; ER, endoplasmic reticulum; Mn, manganese; Qct, quercetin.