Fengyuan Wang

Protective role of sodium selenite on histopathological lesions, decreased T-cell subsets and increased apoptosis of thymus in broilers intoxicated with aflatoxin B1

For evaluating the ability of selenium (Se) in counteracting the adverse effects of aflatoxin B₁ (AFB₁), two hundred 1-day-old male Avian broilers, divided into five groups, were fed with basal diet (control group), 0.3 mg/kg AFB₁ (AFB₁ group), 0.3 mg/kg AFB₁+0.2 mg/kg Se (+Se group I), 0.3mg/kg AFB₁+0.4 mg/kg Se (+Se group II) and 0.3mg/kg AFB₁+0.6 mg/kg Se (+Se group III), respectively. Compared with control group, the decreased relative weight of thymus and percentages of mature thymocytes, congestion in medulla and much debris in cortex of thymus, and the increased apoptotic thymocytes were observed in AFB1 group. However, supplied dietary sodium selenite could increase the relative weight of thymus and percentages of mature thymocytes, and alleviate histopathological lesions. Compared with AFB1 group, the percentages of apoptotic thymocytes detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling method and flow cytometry method in three +Se groups were decreased, the expression of Caspase-3 and Bax, through quantitative real-time PCR and immunohistochemical method, in three +Se groups were decreased, while the expression of Bcl-2 was increased. The results indicate that sodium selenite supplied in the diet, through a mechanism of apoptosis regulation, may ameliorated AFB₁-induced lesions of thymus and accordingly improve the impaired cellular immune function.

Protective effects of sodium selenite against aflatoxin B1-induced oxidative stress and apoptosis in broiler spleen.

The aim of this study was to investigate the possible protective role of sodium selenite on aflatoxin B1-induced oxidative stress and apoptosis in spleen of broilers. Two hundred one-day-old male broilers, divided into five groups, were fed with basal diet (control group), 0.3 mg/kg AFB1 (AFB1 group), 0.3 mg/kg AFB1 + 0.2 mg/kg Se (+Se group I), 0.3 mg/kg AFB1 + 0.4 mg/kg Se (+Se group II) and 0.3 mg/kg AFB1 + 0.6 mg/kg Se (+Se group III), respectively. According to biochemical assays, AFB1 significantly decreased the activities of glutathione peroxidase, total superoxide dismutase, glutathione reductase, catalase and the level of glutathione hormone, while it increased the level of malondialdehyde. Moreover, AFB1 increased the percentage of apoptosis cells by flow cytometry and the occurrence of apoptotic cells by TUNEL assay. Simultaneous supplementation with sodium selenite restored these parameters to be close to those in control group. In conclusion, sodium selenite exhibited protective effects on AFB1-induced splenic toxicity in broilers by inhibiting oxidative stress and excessive apoptosis.

Effects of aflatoxin B1 on oxidative stress markers and apoptosis of spleens in broilers.

The purpose of the present study was to investigate the oxidative damage and apoptosis induced by aflatoxin B1 (AFB1) in spleen of broilers. A total of 200 one-day-old avian male broilers were randomly divided into 4 equal groups of 50 each and were fed for 21 days as follows: a control diet and three AFB1 diets containing 0.15, 0.3, and 0.6 mg AFB1/kg diet. Consumption of AFB1 diets induced oxidative stress in the spleen of chicken as evidenced by reduced glutathione peroxidase, glutathione reductase, and catalase activities, decreased glutathione contents, and increased malondialdehyde contents in explaining the pathogenesis. Flow cytometer method and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling assay revealed that the apoptotic splenocytes were increased in AFB1 groups. The results suggest that AFB1 induced excessive apoptosis of splenic lymphocytes, which is correlated with increased oxidative stress. The present results may be helpful for explaining the pathogenesis of AFB1-induced immunosuppression.

Effect of selenium supplementation on aflatoxin B1-induced histopathological lesions and apoptosis in bursa of Fabricius in broilers

To investigate the effects of sodium selenite against aflatoxin B1 (AFB 1), 200 male Avian broilers, divided into five groups, were fed with basal diet (control group), 0.3 mg/kg AFB1 (AFB1 group), 0.3 mg/kg AFB1 + 0.2 mg/kg Se (+Se group I), 0.3 mg/kg AFB1 + 0.4 mg/kg Se (+Se group II) and 0.3 mg/kg AFB1 + 0.6 mg/kg Se (+Se group III), respectively. Compared with the control group, decreased relative weight of bursa of Fabricius and contents of serum immunoglobulin, more vacuoles and debris in the bursal lymphoid follicle, and increased percentage of apoptotic bursal cells were observed in the AFB1 group. Sodium selenite, however, could increase the relative weight of bursa of Fabricius and contents of serum immunoglobulin, and ameliorate histopathological lesions. The percentages of apoptotic bursal cells, through flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling method, in the three +Se groups were lower than those in the AFB 1 group. Compared with the AFB 1 group, moreover, the mRNA expressions of Bax and Caspase-3 by qRT-PCR in the three +Se groups were decreased, while the expression of Bcl-2 was increased. The results indicate that sodium selenite in diet can protect chicken from AFB 1-induced impairment of humoral immune function by reducing bursal histopathological lesions and percentages of apoptotic bursal cells.

Effects of sodium selenite on the decreased percentage of T cell subsets, contents of serum IL-2 and IFN-γ induced by aflatoxin B1 in broilers

Aflatoxin B1 (AFB1), especially inducing hepatocellular carcinoma and immunosuppression of animals, poses a serious healthy and economic hazard to both humans and livestock. Animal studies have demonstrated that selenium (Se) provides anticarcinogenic and antimutagenic effects against AFB1. However, the effects of Se against AFB1-induced immunosuppression were rarely reported. To test this, three hundred 1-day-old male avian broilers were divided into five groups and fed on control diet (0.4 mg/kg Se), AFB1 group(0.3mg/kg AFB1+0.4 mg/kg Se), AFB1+Se group I(0.3mg/kg AFB1+0.6 mg/kg Se), AFB1+Se group II(0.3mg/kg AFB1+0.8 mg/kg Se) and AFB1+Se group III(0.3mg/kg AFB1+1.0mg/kg Se) for 21 days (n=60/group). Although the body weight in AFB1 group was lower than that in control group at 14 days of age, there no significant differences on body weight among five groups at 7 and 21 days of age. No evident clinical symptoms were observed among five groups from 7 to 21 days of age. The percentages of peripheral blood CD3(+), CD3(+)CD4(+), CD3(+)CD8(+) and the contents of serum IL-2 and IFN-γ in AFB1 group were decreased, compared with those in control group. Compared with those in AFB1 group, the percentages of CD3(+), CD3(+)CD4(+) and CD3(+)CD8(+) T cells in three AFB1+Se groups were increased from 14 to 21 days of age, and the contents of serum IL-2 and IFN-γ in all AFB1+Se groups were increased from 7 to 21 days of age. On the contrary, the percentages of CD3(+), CD3(+)CD4(+) and CD3(+)CD8(+) T cells, and the contents of Serum IL-2 and IFN-γ in AFB1+Se group III were lower than those in AFB1+Se group II. It was concluded that 0.6 and 0.8 mg/kg Se could increase the decreased percentages of peripheral blood T-cell subsets and the contents of serum IL-2 and IFN-γ induced by 0.3mg/kg AFB1 in the diets, and cellular immune function could be improved in chickens.

Effect of Sodium Selenite on Pathological Changes and Renal Functions in Broilers Fed a Diet Containing Aflatoxin B1

To evaluate the renal toxicity of dietary aflatoxin B1 (AFB1) and ameliorating effects of added dietary sodium selenite in broiler, renal histopathological changes, ultrastructural changes, and renal function parameters were monitored at 7, 14, and 21 days of age. Two hundred one-day-old healthy male Avian broilers were divided into four groups, namely control group, AFB1 group (0.3 mg/kg AFB1), +Se group (0.4 mg/kg Se), and AFB1+Se group (0.3 mg/kg AFB1+0.4 mg/kg Se). Compared with that of the control group, the relative weight of kidney was increased in the AFB1 group. There were no significant differences between the AFB1+Se group and the control group. By histopathological observation, the renal epithelia were swelling and necrosis at 7 and 21 days of age. Ultrastructurally, the lipid droplets and expanded endoplasmic reticulum appeared in the plasma of epithelia cells in the AFB1 group. Enlarged mitochondria with degenerated cristae were observed in the +Se group. Compared with the control group, the contents of serum creatinine and serum uric acid in the AFB1 group were increased, while the activity of renal Na+-K+ ATPase was decreased. When 0.4 mg/kg selenium was added into the diet containing 0.3 mg/kg AFB1, there were no obvious histological changes in the AFB1+Se group, and the contents of the serum creatinine and serum uric acid contents and the activity of renal Na+-K+ ATPase were close to those in the control group. In conclusion, sodium selenite exhibited protective effects on AFB1-induced kidney toxicity in broilers.

A study on the expression of apoptotic molecules related to death receptor and endoplasmic reticulum pathways in the jejunum of AFB 1 -intoxicated chickens

Aflatoxin B1 (AFB1) is a common contaminant of poultry feeds in tropical and subtropical climates. Early researches have well established the hepatotoxic, carcinogenic, and immunotoxic effects of AFB1 on humans and animals. Recently, it has been shown that AFB1 could cause the up- or down-alteration of mitochondrial pathway molecule expression. However, the information on the expression of death receptor and endoplasmic reticulum molecules in the jejunal apoptosis induced by AFB1 were unavailable. So the present study was conducted to explore the expression of apoptotic molecules related to death receptor and endoplasmic reticulum in the jejunal cells of chickens exposed to AFB1 diet for 3 weeks. Total of 144 one-day-old chickens was randomly divided into two groups, namely control group (containing 0 mg/kg AFB1) and AFB1 group (containing 0.6 mg/kg AFB1). Histopathological observation and microscopic quantitative analysis revealed morphological changes in the jejunum such as the shedding of the mucosal epithelial cells in the apical region of villi along with the decrease of villus height, villus area and villus/crypt ratio in the AFB1 group. Both TUNEL and flow cytometry assays showed that AFB1 intake induced excessive apoptosis of jejunal cells. Quantitative real-time PCR test displayed the general upregulation of death receptors (FAS, FASL, TNF-α and TNF-R1), endoplasmic reticulum signals (GRP78 and GRP94) as well as initiator and executioner caspases (CASPASE-10, CASPASE-8 and CASPASE-3) in the jejunum of AFB1-intoxicated chickens. Its the first study demonstrating that AFB1 induced apoptosis of chickens’ jejunum accompanied by the alteration of death receptor and endoplasmic reticulum molecule expression.

Histopathological Injuries, Ultrastructural Changes, and Depressed TLR Expression in the Small Intestine of Broiler Chickens with Aflatoxin B1

To explore AFB1-induced damage of the small intestine, the changes in structure and expression of TLRs (Toll-like Receptors) in the small intestine of chickens were systematically investigated. Ninety healthy neonatal Cobb chickens were randomized into a control group (0 mg/kg AFB1) and an AFB1 group (0.6 mg/kg AFB1). The crypt depth of the small intestine in the AFB1 group was significantly increased in comparison to the control chickens, while the villus height and area were evidently decreased, as well as the villus:crypt ratio and epithelial thickness. The histopathological observations showed that the villi of the small intestine exposed to AFB1 were obviously shedding. Based on ultrastructural observation, the absorptive cells of small intestine in the AFB1 group exhibited fewer microvilli, mitochondrial vacuolation and the disappearance of mitochondrial cristae, and junctional complexes as well as terminal web. Moreover, the number of goblet cells in the small intestine in the AFB1 group significantly decreased. Also, AFB1 evidently decreased the mRNA expression of TLR2-2, TLR4, and TLR7 in the small intestine. Taken together, our study indicated that dietary 0.6 mg/kg AFB1 could induce histopathological injuries and ultrastructural changes, and depress levels of TLR mRNA in the chicken small intestine.

Aflatoxin B 1 affects apoptosis and expression of death receptor and endoplasmic reticulum molecules in chicken spleen

Aflatoxin B1 (AFB1) is a natural product of the Aspergillus genus of molds, which grow on several foodstuffs stored in hot moist conditions, and is among the most potent hepatocarcinogens and immunosuppression presently known. The latter was related to the up-regulated apoptosis of immune organs. However, the effect of expression of death receptor and endoplasmic reticulum molecules in AFB1-induced apoptosis of chicken splenocytes was largely unknown. The objective of this study was to investigate this unknown field. One hundred and forty four one-day-old chickens were randomly divided into control group (0 mg/kg AFB1) and AFB1 group (0.6 mg/kg AFB1), respectively and fed with AFB1 for 21 days. Histological observation demonstrated that AFB1 caused slight congestion and lymphocytic depletion in the spleen. TUNEL and flow cytometry assays showed the excessive apoptosis of splenocytes provoked by AFB1. Moreover, quantitative real-time PCR analysis revealed that AFB1 induced the elevated mRNA expression of Fas, FasL, TNF-α, TNF-R1, Caspase-3, Caspase-8, Caspase-10, Grp78 and Grp94 in the spleen. These findings suggested that AFB1 could lead the excessive apoptosis and alter the expression of death receptor and endoplasmic reticulum molecules in chicken spleen.

Histopathological Changes Caused by Inflammation and Oxidative Stress in Diet-Induced-Obese Mouse following Experimental Lung Injury

Obesity has been identified as a risk factor for adverse outcomes of various diseases. However, information regarding the difference between the response of obese and normal subjects to pulmonary inflammation is limited. Mice were fed with the control or high-fat diet to establish the lean and diet-induced obese (DIO) mice. Escherichia coli was intranasally instilled to reproduce non-fatal acute pneumonia model. After infection, serum samples and lung tissues were obtained at 0, 12, 24, and 72 h. DIO mice exhibited increased serum triglyceride (TG) and total cholesterol (TC) contents as well as pulmonary resistin, IL-6, and leptin levels compared with lean mice. E. coli infection caused an acute suppurative inflammation in the lung with increased lung index and serum TG and TC contents; elevated pulmonary tumor necrosis factor-α, interleukin (IL)-1β, IL-6, IL-8, and leptin levels; and oxidative stress in mice. Interestingly, almost all the above-mentioned parameters peaked at 12 h after infection in the lean-E. coli group but after 12 h in the DIO-E. coli group. These results indicated that the DIO mice presented a delayed inflammatory response and oxidative stress in non-fatal acute pneumonia induced by E. coli infection.