Protective effect of Inonotus obliquus polysaccharide on mice infected with Neospora caninum.

The study aimed to explore the protective effects of Inonotus obliquus polysaccharide (IOP) on Neospora caninum (N. caninum) infection. Our data showed that the survival rate of the mice was the highest and the survival time was the longest when the IOP was 2 mg/10 g. In agreement with these observations, IOP alleviated the pathological damage in the various organs and tissues of the mice. Compared with that in the Neosporidium infection model group, the content of N. caninum in the heart, liver, spleen, lung, kidney and brain, determined through HE staining, was significantly lower. In addition, IOP inhibited the levels of immunoglobulin G1 (IgG1) and immunoglobulin G2 (IgG2a) from the 21st to 42nd day of the administration group, whereas the levels of interleukin-12 (IL-12) and serum tumor necrosis factor alpha (TNF-α) were down-regulated at 7 d - 42 d. The production of CD4+ T lymphocytes was promoted, the number of CD8+ T lymphocytes were significantly lower and the CD4+/CD8+ ratio was significantly elevated. Furthermore, IOP effectively balanced the levels of hormones including gonadotropin-releasing hormone (GnRH), luteotropic hormone (LH) and testosterone (T) in male mice, and progesterone (PROG), estradiol (E2) and prolactin (PRL) in female mice. These findings demonstrate that IOP exerts protective effects against pathological damage caused by N. caninum infection in mice, and improve the immune function of the organism and regulate the secretion balance of sex hormones.

A preliminary study on placental damage associated to experimental neosporosis in BALB/c mice.

Neospora caninum is a protozoan parasite which can infect a range of animals, including dogs, cattle, and sheep. Bovine neosporosis, which mainly causes abortion in cattle, results in substantial economic losses worldwide. To study the effects of N. caninum infection on the placenta, a pregnant mouse model for N. caninum infection was established. The litter size (8.6 ± 1.5) and the number of live pups (6.4 ± 1.8) of infected dams were significantly lower compared with those of non-infected dams. Trophoblast cell shrinkage and a large number of apoptosomes were detected in the placentas of the infected group. The parasite load in the placental tissue was significantly higher with time after infection. Likewise, apoptosis of placental trophoblast cells significantly increased with time after infection. Among the 66 apoptotic genes detected in this study, eight genes, including Bcl-2, were significantly differentially expressed by about > tenfold in infected and uninfected mice. The expression of BAX and tumor necrosis factor-alpha (TNF-α) was upregulated in the placental cells of the infected mice, whereas the expression of BCL-2 was downregulated. Enzyme-linked immunosorbent assays (ELISAs) showed that apoptotic protease caspase-3 level was significantly increased in placental cell suspension, and insulin-like growth factor (IGF)-2 level was significantly reduced. Acetylcholine (ACH) and placental prolactin (PL) levels were initially decreased but eventually increased. In summary, infection of mice with N. caninum caused apoptotic damage to the placental tissues, cells, and genes and affected the normal physiological functions of placenta, which may largely explain the adverse pregnancy outcomes caused by N. caninum infection in mice.

Reproductive injury in male BALB/c mice infected with Neospora caninum.

BACKGROUND: Neospora caninum is one of the main causes of abortion in pregnant animals. However, N. caninum-induced reproductive injury in male mice is still unclear. METHODS: Male BALB/c mice were infected with a bovine isolate of N. caninum, and the organ coefficients of the testis and epididymis were measured. Lesions in the testis and epididymis were observed by light microscopy and transmission electron microscopy. Expression of the spermatogenic cell apoptosis-related proteins p53 and caspase-3 was detected by western blot. The expression of spermatogenesis-related genes in the testis was detected by reverse transcription-PCR. Sperm morphology and motility were observed. The levels of nitric oxide (NO) and antisperm antibody (AsAb) in the testicular homogenates and hormones in the serum were detected by enzyme-linked immunosorbent assay. The reproductive capacity of the male mice was detected using a reproduction test. RESULTS: The organ coefficients of the testis and epididymis of the experimental group were significantly downregulated. Light microscopy examination revealed that the spermatogenic cells of the testis were arranged in a disordered manner, and the number was reduced. The number of sperm in the epididymal lumen was significantly reduced, and the cytoplasm exhibited vacuolation and degeneration. Ultrastructural studies revealed that the cells of the testis and epididymis tissues showed varying degrees of disease. The level of p53 and caspase-3 expression in the testis was significantly upregulated. The expression of the testicular spermatogenesis-related genes Herc4, Ipo11 and Mrto4 were strongly downregulated. Observation of sperm by microscopic examination revealed significantly reduced sperm density and sperm motility, and the number of sperm deformities was significantly increased. The level of NO and AsAb was significantly increased. The levels of luteinizing hormone, follicle-stimulating hormone and gonadotropin-releasing hormone were significantly upregulated, whereas the levels of testosterone, thyrotropin-releasing hormone, thyroxine and thyroid-stimulating hormone were significantly downregulated. After challenge, the infected male mice and healthy female mice were caged together: the subsequent fetal death rate was increased, and the conception rate, litter size, number of live births and the birth weight were significantly reduced. CONCLUSIONS: Infection of male BALB/c mice with the bovine isolate of N. caninum induced varying degrees of injury to the testis, epididymis and sperm of the mice, destroyed spermatogenesis and affected the reproductive capacity.

Establishment of a model of Neospora caninum infection in pregnant mice.

The aim of this study was to establish an animal model of Neospora caninum infection in pregnant BALB/c mice infected with different doses of N. caninum tachyzoites. After infection, the female BALB/c mice were housed with male BALB/c mice. The aim of this study was to observe clinical signs and pathological changes, detect Nc5 gene expression in the main organs, and measure the wet weight and coefficient of the placenta of the pregnant mice. In addition, the level of cytokines and placental hormones in the serum was measured in pregnant mice. Our results showed that the optimal dose of the mice in the infected model was 105 tachyzoites. The infected pregnant mice presented with various clinical signs, including depression, ataxia, and variable mortality. Pathological observations of the brain, liver, and spleen in the mice exhibited hyperemia, bleeding, and swelling. Moreover, N. caninum tissue cysts or tachyzoites were observed in the brain, liver, and spleen tissues by hematoxylin-eosin (HE). The Nc5 gene was detected in the brain, liver, spleen, and placental tissues of the mice. With the increase in infection days, the weight of the placenta in the model mice increased, and the placenta ratio decreased gradually. Compared with the control group, the placenta weight and placental ratio were significantly different (P < 0.05). Furthermore, the levels of the placental hormones, corticotropin-releasing hormone (CRH), chorionic gonadotropin (CG), prolactin (PRL), and estriol (E3), and cytokines IFN-γ, IL-4, and TGF-ß were differentially expressed between the model and the control group (P < 0.05 or P < 0.01), which indicated that infection with N. caninum caused an imbalance in the regulatory function of the placental hormones and cytokines in pregnant mice. A pregnant mouse model of N. caninum infection was successfully established in this study, providing a foundation for the study of the pathogenic mechanisms of N. caninum.

First report of genetic diversity and risk factor analysis of equine piroplasm infection in equids in Jilin, China.

BACKGROUND: Equine piroplasmosis (EP) is a tick-borne hemoprotozoan disease of equids, caused by Theileria equi and Babesia caballi. Equine piroplasmosis represents a serious challenge to the equine industry due to important economic losses worldwide. The present study aimed to evaluate the prevalence of Theileria equi and Babesia caballi infections in equids from Jilin Province, China. METHODS: A total of 220 blood samples (192 horses and 28 donkeys/mules) were collected from March 2018 to October 2019 in five districts of Jilin Province and analyzed by PCR. Potential risk factors, including the region, sex, management, and host species of the animals were assessed in relation to T. equi infection. Moreover, the V4 hypervariable region of the T. equi 18S rRNA gene was analyzed to identify specific genotypes. RESULTS: The overall prevalence of T. equi in equids was 27.7%, whereas B. caballi infection was not identified. The district with the highest positive rate was Baicheng (43.3%), followed by Tonghua (28.9%), Yanbian (26.4%), Jilin (23.3%), and Liaoyuan (20.9%). The sex of the animals and farm management were identified as main risk factors, which were significantly associated with the prevalence of Equine piroplasmosis (P < 0.05). The risk factor analysis indicated that the females were at a higher risk (OR: 2.48, 95% CI: 1.17-5.27) of being infected compared to the males, whereas the organized farm was protective factor (OR: 0.42, 95% CI: 0.22-0.80). The phylogenetic analyses revealed that there were two T. equi genotypes (A and E) in Jilin. CONCLUSIONS: Our findings provided important epidemiological data for the prevention and control of T. equi infection in Jilin, China.

Molecular prevalence of Theileria infections in cattle in Yanbian, north-eastern China.

Bovine Theileria are tick-borne protozoan parasites that invade bovine erythrocytes and lymphocytes. Three main bovine Theileria species have been identified in China: T. orientalis, T. sinensis, and T. annulata. To examine the prevalence of bovine theileriosis in Yanbian, a total of 584 bovine blood samples were collected from five localities from 2017 to 2019 and analyzed by PCR. Six pairs of oligonucleotide primers directed against the 18S rRNA gene of Theileria spp., Tams-1 gene of T. annulata, MPSP gene of T. orientalis, and T. sinensis, were used to detect these parasites. A sequence analysis of the amplified genes confirmed that the Theileria species were T. orientalis and T. sinensis, without T. annulata. The overall prevalence of Theileria in cattle was 42.81% (250/584). Out of the 584 samples, 159 (27.23%) and 157 (26.88%) were positive for T. sinensis and T. orientalis, respectively, and the mixed infection rate was 11.30% (66/584). The total prevalence of bovine Theileria species in Helong, Hunchun, Longjing, Yanji, and Dunhua was 66.28%, 49.68%, 23.81%, 28.15%, and 0%, respectively. These results provide epidemiological data for the prevention and control of bovine Theileria species in Yanbian, China.

TITLE: Prévalence moléculaire des infections à Theileria chez les bovins à Yanbian, dans le nord-est de la Chine. ABSTRACT: Les Theileria bovins sont des parasites protozoaires transmis par les tiques qui envahissent les érythrocytes et les lymphocytes des bovins. Trois espèces principales de Theileria de bovins ont été identifiées en Chine, T. orientalis, T. sinensis et T. annulata. Pour examiner la prévalence de la theilériose bovine à Yanbian, un total de 584 échantillons de sang bovin ont été collectés dans cinq localités de 2017 à 2019 et analysés par PCR. Six paires d'amorces oligonucléotidiques dirigées contre le gène d'ARNr 18S de Theileria spp., le gène Tams-1 de T. annulata et le gène MPSP de T. orientalis et T. sinensis, ont été utilisées pour détecter ces parasites. Une analyse de séquence des gènes amplifiés a confirmé que les espèces de Theileria étaient T. orientalis et T. sinensis, sans T. annulata. La prévalence globale des Theileria chez les bovins était de 42,81 % (250/584). Sur les 584 échantillons, 159 (27,23 %) et 157 (26,88 %) étaient positifs pour T. sinensis et T. orientalis, respectivement, et le taux d'infection mixte était de 11,30 % (66/584). La prévalence totale des espèces bovines de Theileria à Helong, Hunchun, Longjing, Yanji et Dunhua était respectivement de 66,28 %, 49,68 %, 23,81 %, 28,15 % et 0 %. Ces résultats fournissent des données épidémiologiques pour la prévention et le contrôle des espèces de Theileria de bovins à Yanbian, en Chine.

Construction of an Adenovirus Vaccine Expressing the Cross-reactive Antigen AMA1 for Neospora caninum and Toxoplasma gondii and Its Immune Response in an Animal Model.

BACKGROUND: We aimed to construct an adenovirus expressing a cross-reactive fragment of the apical membrane antigen 1 (AMA1) antigen and evaluated the concomitant immune response in BABL/c mice, allowing protection against N. caninum and T. gondii infection. METHODS: The study was conducted in Agricultural College of Yanbian University, Yanji, Jilin, China In 2015-2016. Primers were designed using the AMA1 gene sequences of N. caninum (AB265823.1) and T. gondii (AF010264.1). After linearization of the plasmid ADV4-NcAMA1 and the framework plasmid pacAd5, a total of 293T cells were cotransfected and Ad5-NcAMA1 recombinant adenovirus were packed. BALB/c mice were inoculated. Simultaneously serum IgG antibody levels and IFN-γ and IL-4 cytokine levels were determined by ELISA. After immunization three times in two weeks, each group of BABL/c mice were divided into two groups, respectively given intraperitoneal inoculation by the Neospora tachyzoite and Toxoplasma tachyzoite. Then we observed the clinical symptoms and statistical survival rate of mice. RESULTS: The level of IgG in BABL/c mice immunized with Ad5-NcAMA1 was significantly increased when compared with that of pVAX1-NcAMA1 and PBS groups (P<0.01). At the same time, the cytokine levels of IFN-γ and IL-4 were also higher in the Ad4-NcAMA1 group than in the control groups (P<0.01). Moreover, BABL/c mice immunized with Ad5-NcAMA1, pVAX1-NcAMA1, and PBS showed survival rates of 75%, 45% and 20% after N. caninum infection, and 45%, 10% and 0% after T. gondii infection, respectively. CONCLUSION: The adenovirus vaccineAd5-NcAMA1 could provide protective immunity against N. caninum and T. gondii infection.