[Effect of horizontal rotary culture on zebrafish vascular development]

With the development of space life science, a study on the influence of microgravity on organism has been an increasingly concerned topic. Lots of studies indicate that microgravity plays an important role in the early development of embryos. The vascular system as the first-function system of embryos provides an interesting topic for many researchers. However, those studies were mostly carried out in vitro by rotary cell culture system (RCCS), while few experiments were done in vivo. Using zebrafish as a model, this research investigated the effects of horizontal rotary culture on the vascular development in vivo. Zebrafish embryos at 24 hpf (hour post-fertilization) were selected and divided into two groups. One group was cultured by the shaker, and the other was cultured normally as the control. After 12 h, all the embryos were collected and detected. The phenotype of zebrafish was observed by stereo microscope. Then, the expression of vascular specific expression factor, flk1, flt4, and ephrinB2 was compared by RT-PCR, qPCR, and in situ hybridization, respectively. Cell apoptosis and proliferation in situ were observed using TUNEL assay and bromodeoxyuridine incorporation. The results demonstrated that horizontal rotary culture at 90 r/min decreased the hatching of embryos (10.3±0.41 vs. 0.0, P<0.05), accelerate the heart rate (223.5±2.32 vs. 185.0±3.23, P<0.05) and increased the content of melanin in zebrafish significantly. At the same time, we found some differences in the vascular system of zebrafish after horizontal rotary culture which caused a down regulation of flk1, flt4, and ephrinB2. On the other hand, horizontal rotary culture accelerated the apoptosis of cells in zebrafish, but showed no significance in proliferation. In conclusion, horizontal rotary culture has a significant influence on the vascular development in zebrafish.