Stimulatory effect of icariin on the proliferation of neural stem cells from rat hippocampus
Healthy SPF Sprague-Dawley rats (220 to 260 g) were obtained from the Experimental Animal Center of Daping Hospital, Research Institute of Surgery, Third Military Medical University (SPFgrade, Certificate NO. SCXK 2012–0005). The animals were maintained under a 12 h light/dark cycle in temperature (23 ± 1 °C) and humidity (relative, 60%)-controlled rooms and allowed free access to food and water. All animal experiments were strictly carried out in accordance with NIH guidelines for the Care and Use of Laboratory Animals (NIH Publications No. 80–23, revised 1996), and the study protocol was approved by the Animal Experimentation Ethics Committee of Zunyi Medical University.The cellular morphology of neural stem cells was examined by microscopy for changes in appearance during each passage. Neural stem cells are capable of forming in vitro into neurospheres, which possess three fundamental characteristics: proliferation, self-renewal, and multipotency . It was observed that new floating neurospheres containing varying number of cells were formed at day 3 of the culture as a consequence of cell growth and proliferation. These cellular neurospheres were identified as well-defined spherical cell clusters as well as more irregular cell clusters (Fig. 1). Cilia were also present on the surface or outer edges of some of the neurospheres, indicating that the neurospheres were in a healthy condition. The neurospheres were found to be capable of self-renewal while in the culture of neural stem cell medium.All animal experiments were strictly carried out in accordance with NIH guidelines for the Care and Use of Laboratory Animals (NIH Publications No. 80–23, revised 1996), and the study protocol was approved by the Animal Experimentation Ethics Committee of Zunyi Medical College.Electronic supplementary materialThe online version of this article (10.1186/s12906-018-2095-y) contains supplementary material, which is available to authorized users.