Type 2 innate lymphoid cell-derived amphiregulin regulates type II alveolar epithelial cell transdifferentiation in a mouse model of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a common complication in preterm infants characterized by alveolar growth arrest. Interleukin (IL)-33 and type 2 innate lymphoid cell (ILC2) affect type II alveolar epithelial cell (AECII) differentiation in BPD mice and may cause increased lung epithelial-mesenchymal transition (EMT). Amphiregulin (AREG) can be produced by ILC2 and is associated with tissue repair. However, the action mechanism of AREG produced by ILC2 to alveolar development in BPD is unclear. In this study, we aimed to demonstrate the role and mechanism of AREG in influencing AECII transdifferentiation in the lung tissue of BPD mice. The effects of ILC2-derived AREG on AECII transdifferentiation were verified in vivo and in vitro, and the role of IL-33 on ILC2-derived AREG in AECII transdifferentiation in BPD mice and a preliminary investigation of the role of AREG's receptor-epidermal growth factor receptor (EGFR) on AECII transdifferentiation. The results showed that neonatal mice developed severe lung injury after hyperoxia, and IL-33 induced AREG production via ILC2 affected normal AECII differentiation and promoted EMT. In addition, the blockade of EGFR was found to alleviate the impaired AECII differentiation under hyperoxia in an in vitro study. In summary, our study demonstrates that AREG secreted by ILC2 affects AECII transdifferentiation in BPD mice, which provides a new idea for the clinical treatment of BPD.

Comparison of four infectious bursal disease viruses isolated from different bird species

Four isolates of infectious bursal disease virus (IBDV), isolated from chicken, duck, goose and sparrow in Jiangsu province of China in 2002, were compared. The viruses were stable to the treatments of 60 degrees C for 1 h, pH 2.0 and lipid solvents. Their antigenic relatedness values (R) were from 0.76 to 0.78. Chickens infected with the chicken isolate showed severe clinical symptoms of IBD and the mortality rate was 33.3% (2/6). Chickens infected with the other three viruses survived but their bursas were damaged and the bursa/body-weight ratios were lower than those of the uninfected control (p< 0.01). The titers of anti-IBDV antibody in infected chicken sera reached up to 1600 by virus neutralization and 6400 by ELISA at 10 days post infection. The sequences of the variable region of VP2 were aligned and compared, showing nucleotide variations ranging from 1.5 to 6.7% and deduced aminoacid variations from 0.8 to 2.2%. All had the same heptapeptide, S-W-S-A-S-G-S, Asp279, and Ala284. The four viruses clustered on a phylogenetic tree and were distant from the STC strain. These findings suggested that different bird species naturally infected with IBDV could serve as carriers or reservoirs in IBDV transmission and might play a role in the emergence of variant IBDV.

Coronavirus as an agent of neonatal calf diarrhea in a Chinese dairy cattle farm

Neonatal calf diarrhea is a significant health problem in dairy industry in the whole world. Although the aetiological agents of neonatal diarrhea are diverse, it is obvious that viruses play an important role. One of them is bovine coronavirus (BCV). Since BCV was discovered (MEBUS et al., 1969), there have been many published reports describing the virus and its importance in calves. In China, we first investigated the seroepidemiological status of BCV infections in cattle (YAO et al., 1990). The results showed that the incidence of infections with BCV in cattle in different chinese regions are high. Further work on direct diagnosis of BCV as a causative agent of diarrhea was therefore necessary. In the last years we have developed diagnostic methods including a monoclonal antibody-based ELISA to detect BCV and other diarrheal viruses. In this study, the diagnosis of an outbreak of BCV in chinese dairy cattle is described.

Age-related differences in the release of luteinizing hormone and gonadotropin-releasing hormone in ovariectomized rats

The effect of aging on the release of gonadotropin-releasing hormone (GnRH) in vitro and of luteinizing hormone (LH) both in vivo and in vitro in ovariectomized (Ovx) rats was studied. Old (21-24 months) and young (3-4 months) rats were Ovx before use. They were injected subcutaneously with estradiol benzoate (25 micrograms/kg) or sesame oil for 3 days and then challenged with GnRH (0.5, 2 or 10 micrograms/kg) via a jugular catheter. Blood samples were collected immediately before and at 5, 10, 20, 40 and 60 min following GnRH injection. For in vitro study, Ovx rats were decapitated. The anterior pituitary glands (APs) were incubated with GnRH (0.1 or 10 nM) and estradiol (0, 0.1, 1 or 10 nM) at 37 degrees C for 30 min. The mediobasal hypothalamus was superfused with Locke's solution at 37 degrees C for 210 min, and stimulated with 60 mM KCl at 90 and 150 min. The medium samples were collected at 10-min intervals. Concentrations of GnRH and LH in plasma and medium samples were measured by radioimmunoassay. In all rats, the basal and GnRH-stimulated levels of plasma LH were lower in old than in young rats. The spontaneous release of LH in vitro from APs of Ovx rats was increased by aging, whereas GnRH-stimulated release of LH in vitro was lower in old than in young animals. The potassium-stimulated, but not spontaneous, release of GnRH was lower in old than in young Ovx rats.(ABSTRACT TRUNCATED AT 250 WORDS)