Zandong Li

Comparison of the expression of cytokine genes in the bursal tissues of the chickens following challenge with infectious bursal disease viruses of varying virulence

BackgroundCytokines are important mediators and regulators of host responses against foreign antigen, with their main function to orchestrate the functional activities of the cells of the immune system. However little is known about the role of cytokines in pathogenesis and immune responses caused by infectious bursa disease virus (IBDV). The aim of this study was to examine the transcripts of cell-mediated immune response-related cytokine genes in the bursal tissues of chickens infected with IBDVs of varying virulence to gain an understanding of pathological changes and mechanisms of immunosuppression caused by IBDV infection and the immune responses evoked.ResultsReal-time quantitative PCR analysis revealed that the expression levels of both Th1 [interferon (IFN)-γ, interleukins (IL)-2 and IL-12p40] and Th2 (IL-4, IL-5, IL-13 and IL-10) cytokines were significantly up-regulated following challenge with the H strain (vvIBDV) and up to 2- and 30-fold, respectively (P < 0.05). Following infection with the Ts strain (cell-adapted virus) these cytokine transcripts were up-regulated at 5 days post-infection (dpi), 2- and 13-fold respectively (P < 0.05), while the expression levels of IL-2 and IL-4 were not significantly different (P > 0.05). A higher degree of cytokine expression was induced by the H strain compared with the Ts strain.ConclusionThe results indicate that the expression of cell-mediated immune-related cytokine genes is strongly induced by IBDV, especially by the vvIBDV, H strain and reveal that these cytokines could play a crucial role in driving cellular immune responses during the acute phase of IBDV infection, and the cellular immune responses caused by IBDV of varying virulence are through different signaling pathways.

Development-promoting effect of chicken embryo membrane on chicken ovarian cortical pieces of different age

Ovarian cortical tissues of various ages of chicken were grafted underneath chorioallantoic membrane (CAM) of 6-d-old chicken embryo and the grafts were collected on d 0, 2, 4, 8, or 10. The tissue sections were prepared to examine the development of follicles in grafts and the proliferative ability of follicles was examined by immunohistochemistry analysis of proliferating cell nuclear antigen. The results indicated that the development of follicles in cultured chicken ovarian cortical pieces progressed smoothly and slowly similar to those in vivo, and the environment of chicken embryo was more suitable for the synchronous development of oocyte and follicular cells in the larger follicles. Meanwhile, the synchronous development could be more easily achieved in the chicken ovarian tissues of 12- to 15-wk chicken. Neither oocyte nor granulosa cells but the thecal cells of follicles developed in grafts of 13- to 15-d chicken within 10 d of culturing in ovo, and the CAM can ease follicular atresia in chicken ovarian grafts of 12- to 15-wk chicken. The proliferative performance of follicles in the grafts was not influenced by the environment of chicken embryo. These results indicated that the chicken embryo has the ability to support slow development of primordial and primary follicles in grafted ovarian cortical tissues of chickens of different ages. The CAM system may also prove useful for the study of early follicle development with further information.

Sexing chick mRNA: A protocol based on quantitative real-time polymerase chain reaction.

&NA; The accurate identification of sex in birds is important for research on avian sex determination and differentiation. Polymerase chain reaction (PCR)‐based methods have been widely applied for the molecular sexing of birds. However, these methods have used genomic DNA. Here, we present the first sexing protocol for chick mRNA based on real‐time quantitative PCR. We demonstrate that this method can accurately determine sex using mRNA from chick gonads and other tissues, such as heart, liver, spleen, lung, and muscle. The strategy of this protocol also may be suitable for other species in which sex is determined by the inheritance of sex chromosomes (ZZ male and ZW female).

Effects of 2,2',5,5'-tetrachlorobiphenyl (PCB52) on migration of chicken primordial germ cells

Polychlorinated biphenyls cause developmental and physiological anomalies in the reproductive system. This study investigated the effects of 2,22,5,52-tetrachlorobiphenyl (PCB52), which can produce oestrogenic effects on the homeostasis of chicken primordial germ cells from the initial stage until completion of their settlement in the gonadal primordium. The blastoderm of chicken embryos was injected with 1 (1/4)L PCB52 (10 micromol/L) and oestradiol (100 micromol/L) before incubation, and the number of primordial germ cells was determined during their migration and development. The number of primordial germ cells in germinal crescents in PCB52-treated groups was slightly decreased (P = 0.068), but it was reduced significantly at stages 13-15 and 28-30 (P < 0.01, respectively) compared with controls. No obvious effects on primordial germ cell migration were observed with oestradiol treatments. The present results suggest that the influence of PCB52 on chicken primordial germ cell migration and proliferation may be via its toxic effect, not its oestrogen-mimicking effect, and provide information on the sensitivity of primordial germ cells to the direct action of PCB52.