[Show abstract][Hide abstract] ABSTRACT: This study investigated the effects of long-term simulated weightlessness on liver morphology, enzymes, glycogen, and apoptosis related proteins by using two-month rat-tail suspension model (TS), and liver injury improvement by rat-tail suspension with resistance training model (TS&RT). Microscopically the livers of TS rats showed massive granular degeneration, chronic inflammation, and portal fibrosis. Mitochondrial and endoplasmic reticulum swelling and loss of membrane integrity were observed by transmission electron microscopy (TEM). The similar, but milder, morphological changes were observed in the livers of TS&RT rats. Serum biochemistry analysis revealed that the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were significantly higher (p<0.05) in TS rats than in controls. The levels of ALT and AST in TS&RT rats were slightly lower than in RT rats, but they were insignificantly higher than in controls. However, both TS and TS&RT rats had significantly lower levels (p<0.05) of serum glucose and hepatic glycogen than in controls. Immunohistochemistry demonstrated that the expressions of Bax, Bcl-2, and active caspase-3 were higher in TS rats than in TS&RT and control rats. Real-time polymerase chain reaction (real-time PCR) showed that TS rats had higher mRNA levels (P < 0.05) of glucose-regulated protein 78 (GRP78) and caspase-12 transcription than in control rats; whereas mRNA expressions of C/EBP homologous protein (CHOP) and c-Jun N-terminal kinase (JNK) were slightly higher in TS rats. TS&RT rats showed no significant differences of above 4 mRNAs compared with the control group. Our results demonstrated that long-term weightlessness caused hepatic injury, and may trigger hepatic apoptosis. Resistance training slightly improved hepatic damage.
[Show abstract][Hide abstract] ABSTRACT: Newcastle disease, which is caused by Newcastle disease virus (NDV), is a highly contagious viral disease of poultry and other bird species. The mucosa is the first line of defence to invading pathogens, including NDV, and it has been confirmed that the mucosa can contribute to host protection. This study was conducted to evaluate the intestinal mucosal immunology in NDV infection. Forty specific-pathogen-free chickens were divided into two groups, 20 birds in each group. Group 1 was inoculated with NDV by the intravenous route. Group 2 was used as the control group and was given sterile phosphate-buffered saline by the same route. At 24, 48, 72, and 96 h post infection (h.p.i.), five chickens from each treatment were killed. Samples of the duodenum, jejunum, and ileum were collected to quantify intestinal intraepithelial lymphocytes (IEL), goblet cells and secretory IgA (sIgA) by cytochemistry and immunohistochemistry analysis. The results indicated that IEL were increased from 24 to 72 h.p.i. in the infected tissues, and were significantly higher than in the control group at 48 h.p.i. (P < 0.01). In contrast to IEL, goblet cell numbers were reduced dramatically from 24 to 96 h.p.i. in the infected birds (P < 0.01) Furthermore, the content of sIgA was significantly higher at 48 and 72 h.p.i. in the infected tissues (P < 0.01). sIgA positivity was observed in the epithelial lining of the intestinal mucosa. These data suggest that IEL, goblet cells, and sIgA were involved in the intestinal mucosal immunity against NDV infection.
[Show abstract][Hide abstract] ABSTRACT: The toxicity of melamine has attracted much attention since the recent outbreaks of renal injury in pets and infants. Previous studies indicated that melamine by itself had low toxicity, whereas a mixture of melamine and cyanuric acid (M+CA) could cause serious renal damage. At present, most researches on the toxicity of M+CA are focused on the kidney. However, little is known about the adverse effects of this mixture on the reproductive system. In the present study, the toxicity of M+CA to testes was investigated. Immature male mice were orally dosed with 0, 0.6, 3, and 15 mg kg−1 d−1 of a 1:1 M+CA for 28 d. Pathological changes occurred in germ cells, such as loose arrangement, reduced numbers and karyopyknosis, indicating that this mixture was toxic to spermatogenesis. Compared with the control group, the TUNEL-positive germ cells increased significantly and the ratio of Bcl-2 to Bax, total antioxidant capacity and superoxide dismutase activity decreased significantly in the 3 and 15 mg kg−1 d−1 M+CA treated group, while the activities of caspase-3, caspase-8 and caspase-9 remained unchanged. The results suggest that M+CA can induce apoptosis in the mice testes. The downregulation of Bcl-2/Bax and oxidative stress may play a pivotal role in the induction of apoptosis by M+CA in mice testes.
No preview · Article · Dec 2012 · Journal of Integrative Agriculture
[Show abstract][Hide abstract] ABSTRACT: Bisphenol A (BPA) is a chemical estrogen widely used in the food packaging industry, especially in baby bottles. Its toxicity for the fetus has become a great concern in recent years. In the present study, the effects of BPA on the development of central immune organs in chick embryos were investigated. A total of 30 specific-pathogen-free (SPF) chick embryos were divided into BPA, control, and vehicle group. Chick embryos were exposed to BPA (250 μg per egg), saline (control), or corn oil (vehicle) on embryonic day 9 (ED9) by injection into the allantoic cavity. Thymuses and bursae of Fabricius were collected on ED22. The microscopic examination of tissue structure and ultrastructure was carried out for histopathological changes of thymus and the bursa of Fabricius morphology under light and scanning electron microscopes (SEM). In the BPA group, the weight index of the bursae of Fabricius was significantly reduced (p < 0.01); the number of lymphatic follicles in the bursae of Fabricius was remarkably decreased (p < 0.01); and the thickness of the thymus cortex and medulla was reduced (p < 0.01). Light microscope and SEM examinations further showed that the lymphatic follicles and epithelial cells of the bursa of Fabricius and thymus were damaged by BPA. Our study confirms a direct toxicity of BPA at a very low-dose level on the development of the central immune organs of SPF chick embryos. However, more studies are necessary to elucidate the underlying mechanisms.
No preview · Article · Jul 2012 · Toxicology and Industrial Health
[Show abstract][Hide abstract] ABSTRACT: Skeletal unloading induced by disuse or immobilization causes a decrease in bone mass and strength. We investigated the relationship between whole-body vibration (WBV) and resistance exercise (RE) in preventing bone loss induced by 8-week hindlimb unloading in young male rats. Sixty male Wistar rats were assigned randomly to 6 groups: age-matched control group (CON, n = 10), hindlimb unloading group (HU, n = 10), hindlimb unloading + standing group (HU + ST, n = 10), hindlimb unloading + WBV group (HU + WBV, n = 10), hindlimb unloading + RE group (HU + RE, n = 10) and hindlimb unloading + WBV + RE group (HU + WBV + RE, n = 10). After 8-week hindlimb unloading, micro-CT scanning and three-point bending test were performed in the femur. Sera were collected for analysis of bone formation and resorption markers. Compared with HU group, WBV, RE and the combination of WBV and RE (WBV + RE) significantly improved (P < 0.01) one repetition maximum (1RM) (expressed as the percentage change from baseline, HU: -23%, HU + WBV: 21%, HU + RE: 48%, HU + WBV + RE: 51%), and maintained (P < 0.05) cancellous volumetric bone mineral density (vBMD) and trabecular structure. No difference of cortical vBMD was found among all groups (P > 0.05). WBV had no effects on biomechanical properties of the femur diaphysis (P > 0.05). RE and WBV + RE significantly increased maximum load and cross-sectional moment of inertia of the femur diaphysis in hindlimb unloading rats (P < 0.05). There was an interaction between WBV and RE in improving cancellous bone. These results demonstrate that WBV and RE interactively maintain cancellous structure and vBMD, and independently partially mitigate the reduction of bone strength in long-term hindlimb unloading rats.
No preview · Article · Feb 2012 · Arbeitsphysiologie
[Show abstract][Hide abstract] ABSTRACT: Hepatitis B virus (HBV) is one of the most important human pathogens. Its existence in food animals could present a significant threat to public health. The objective of this study was to determine if HBV is present in serum and liver of chickens. A total of 129 serum samples from broiler chickens were collected for the detection of HBV antigens and antibodies, and 193 liver samples were tested for HBV DNA sequence by PCR and for the existence of HBV antigens by immunohistochemistry. The overall prevalence of HBsAg, anti-HBs, anti-HBc was 28.68%, 53.49%, 17.05%, respectively, whereas HBeAg, anti-HBe were barely detectable. Three serum samples were found to be positive for both HBsAg and HBeAg. Further analysis of these samples with transmission electron microscopy (TEM) revealed two morphologic particles with 20 nm and 40 nm in diameter, which were similar to small spherical and Danes particles of HBV. The viral DNA sequence identified in two of the chicken livers shared 92.2% of one known HBV strain and 97.9% nucleotide sequence of another HBV strain. Our results showed the existence of HBV in chickens. This would present a significant risk to people who work with live chickens or chicken products if HBV found in chicken could be confirmed to be the same as human HBV.
[Show abstract][Hide abstract] ABSTRACT: To explore whether an environment of weightlessness will cause damage to the reproductive system of animals, we used the tail-suspension model to simulate microgravity, and investigated the effect of microgravity on the tissue structure and function of the testis in sexually mature male rats. Forty-eight male Wistar rats weighing 200-250 g were randomly assigned to three groups (N = 16 each): control, tail traction, and tail suspension. After the rats were suspended for 7 or 14 days, morphological changes of testis were evaluated by histological and electron microscopic methods. The expression of HSP70, bax/bcl-2 and AR (androgen receptor) in testis was measured by immunohistochemistry. Obvious pathological lesions were present in the testis after the rats were suspended for 7 or 14 days. We detected overexpression of HSP70 and an increase of apoptotic cells, which may have contributed to the injury to the testis. The expression of AR, as an effector molecule in the testis, was significantly decreased in the suspended groups compared to control (P < 0.01). We also observed that, with a longer time of suspension, the aforementioned pathological damage became more serious and some pathological injury to the testis was irreversible. The results demonstrated that a short- or medium-term microgravity environment could lead to severe irreversible damage to the structure of rat testis.
Preview · Article · Dec 2011 · Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas / Sociedade Brasileira de Biofisica ... [et al.]
[Show abstract][Hide abstract] ABSTRACT: Eimeria tenella, one of the seven species of chicken coccidia, elicits protective immunity against challenge infection with both homologous and heterologous strains. We endeavor to use recombinant E. tenella as a vaccine vehicle for expressing and delivering pathogen Ags and investigate immune responses against these foreign Ags. In this study, two lines of transgenic E. tenella expressing a model Ag, enhanced yellow fluorescent protein (EYFP), targeted to the micronemes and to the cytoplasm of the recombinant parasites were constructed to study the impact of Ag compartmentalization on immunogenicity. The MTT assay, intracellular cytokine staining, and real-time PCR were performed to detect the EYFP-specific proliferation and effector functions of splenic lymphocytes of immunized chickens. ELISA was used to measure anti-EYFP IgG and IgA responses. The results showed that both lines of transgenic parasites stimulated EYFP-specific lymphocyte proliferation and IFN-γ expression in CD4 and CD8 T cells, whereas a higher level of Ag-specific lymphocyte proliferation was elicited by the transgenic line expressing microneme-targeted EYFP. Furthermore, this line stimulated stronger IgA response than the one expressing cytoplasm-targeted EYFP after the second immunization. Our findings are encouraging for further investigation of the effect of Ag compartmentalization in transgenic Eimeria on immunogenicity and for the development of a eukaryotic vaccine vector using genetically modified Apicomplexa parasites.
Full-text · Article · Aug 2011 · The Journal of Immunology
[Show abstract][Hide abstract] ABSTRACT: Toxoplasma gondii has been shown to trigger strong cellular immune responses to heterologous antigens expressed by the parasite in the inbred mouse model. We studied the immune response induced by T. gondii as an effective vaccine vector in chickens and rabbits.
T. gondii RH strain was engineered to express the yellow fluorescent protein (YFP) in the cytoplasm. A subcutaneous injection of the transgenic T. gondii YFP in chickens afforded partial protection against the infection of transgenic E. tenella YFP. T. gondii YFP induced low levels of antibodies to YFP in chickens, suggesting that YFP specific cellular immune response was probably responsible for the protective immunity against E. tenella YFP infection. The measurement of T-cell response and IFN-γ production further confirmed that YFP specific Th1 mediated immune response was induced by T. gondii YFP in immunized chickens. The transgenic T. gondii stimulated significantly higher YFP specific IgG titers in rabbits than in chickens, suggesting greater immunogenicity in a T. gondii susceptible species than in a resistant species. Priming with T. gondii YFP and boosting with the recombinant YFP can induce a strong anti-YFP antibody response in both animal species.
Our findings suggest that T. gondii can be used as an effective vaccine vector and future research should focus on exploring avirulent no cyst-forming strains of T. gondii as a live vaccine vector in animals.
Full-text · Article · Aug 2011 · Parasites & Vectors
[Show abstract][Hide abstract] ABSTRACT: To explore the effects of long-term weightlessness on the renal tissue, we used the two months tail suspension model to simulate microgravity and investigated the simulated microgravity on the renal morphological damages and related molecular mechanisms. The microscopic examination of tissue structure and ultrastructure was carried out for histopathological changes of renal tissue morphology. The immunohistochemistry, real-time PCR and Western blot were performed to explore the molecular mechanisms associated the observations. Hematoxylin and eosin (HE) staining showed severe pathological kidney lesions including glomerular atrophy, degeneration and necrosis of renal tubular epithelial cells in two months tail-suspended rats. Ultrastructural studies of the renal tubular epithelial cells demonstrated that basal laminas of renal tubules were rough and incrassate with mitochondria swelling and vacuolation. Cell apoptosis in kidney monitored by the expression of Bax/Bcl-2 and caspase-3 accompanied these pathological damages caused by long-term microgravity. Analysis of the HSP70 protein expression illustrated that overexpression of HSP70 might play a crucial role in inducing those pathological damages. Glucose regulated protein 78 (GRP78), one of the endoplasmic reticulum (ER) chaperones, was up-regulated significantly in the kidney of tail suspension rat, which implied that ER-stress was associated with apoptosis. Furthermore, CHOP and caspase-12 pathways were activated in ER-stress induced apoptosis. Resistance training not only reduced kidney cell apoptosis and expression of HSP70 protein, it also can attenuate the kidney impairment imposed by weightlessness. The appropriate optimization might be needed for the long term application for space exploration.
[Show abstract][Hide abstract] ABSTRACT: An ideal animal model for hepatitis E virus (HEV) research is still unavailable. To assess the possibility of using Mongolian gerbils as animal model, 28 gerbils were randomly assigned into two groups, 14 for each group. Gerbils in Group 1 were inoculated with a genotype 4 HEV recovered from swine via the intraperitoneal route. Group 2 was used as a negative control and inoculated with normal suspension of swine liver. Sera and feces samples were collected once a week for 7 weeks. Two gerbils from both groups were necropsied weekly, pathological changes were recorded and tissue samples collected for further investigation. Distribution of the virus antigens was determined by immunohistochemical staining. Nested RT-PCR and a commercial ELISA kit were used to confirm the infection. Research results demonstrated that Mongolian gerbils in Group 1 were successfully infected with HEV. Viremia and fecal virus shedding lasted nearly 4 weeks, while the virus could be detected constantly in the liver, and occasionally in the kidneys and spleen as well as the small intestine. Histopathological changes in the liver were present with slight, multifocal, lymphohistiocytic infiltrates in the portal tracts or distributed irregularly throughout the liver. HEV antigens could be detected in the liver and intestine, and were mainly distributed in the nuclei. The results indicate that Mongolian gerbils could be used as an ideal animal model for the study of HEV.
No preview · Article · Sep 2009 · Journal of Medical Virology
[Show abstract][Hide abstract] ABSTRACT: In addition to their well-characterized role in allergic inflammation, recent data confirm that mast cells play a more extensive role in a variety of viral infections. The contribution of mast cells to Newcastle disease pathogenesis has not been investigated. We evaluated mast cell activity after Newcastle disease virus (NDV) infection in specific pathogen free chickens using cytochemical and immunocytochemical analyses. The results were as follows. Severe tissue damage was observed in the proventriculus, duodenum, jejunum and caecal tonsil, and NDV antigens were detected and presented extensively in these tissues. Second, in the NDV-infected group, the mast cell population was increased markedly in the proventriculus, duodenum, jejunum and caecal tonsil at 24, 48, 72 and 96 h after infection (P<0.01). However, very few mast cells were observed in those same tissues in the control. More intriguingly, the greatest number of mast cells was found in the proventriculus, which also showed the greatest level of NDV antigens. Third, the content of tryptase was significantly higher (P<0.01) in the NDV-infected group compared with the control from 24 to 96 h post infection). Furthermore, as an important protease released by mast cells, tryptase had a positive correlation with mast cell distribution. These data indicated that mast cells were involved in the response to NDV. Our results also suggested that the broad range of mast cell mediators might have a role in the pathology of Newcastle disease.