β3肾上腺素受体介导多巴胺对大鼠远端结肠运动的抑制作用

目的建立超声引导下的干细胞山羊宫内移植的方法。方法首先获得胎羊腹部横断面的超声图像，然后在超声引导下将7号穿刺针快速刺入妊娠45～55d的胎羊腹腔内，将外源干细胞注射入胎羊腹腔中，并定期观察受体胎羊在移植后的生长发育和流产情况以及出生后外源细胞的嵌合比例。结果通过超声引导能准确安全地进行外源干细胞的宫内移植，在移植的49头胎羊中，有36头胎羊顺利出生，其余13头流产（流产率26．5％，13／49），与非移植组流产率相当，明显低与剖腹手术移植组（流产率6％）。结论超声引导下的干细胞宫内移植是一种简便和安全的方法，能有效避免剖腹手术方法带来的高流产率，非常适用于宫内移植嵌合体模型的制备，从而为研究干细胞在体内生物学特征和干细胞宫内移植的临床应用提供了技术手段。

Establishment of Human/Goat Stem Cell Chimerism Model via an in Utero Transplantation Under Sonographic Guidance

Objective To establish a non-surgical method for in utero transplantation of stem cells into goats under sonographic guidance. Methods Human hematopoitic stem cells from cord blood were delivered into the peritoneal cavities of the fetal goats at 45-55 days of gestation under sonographic guidance （displaying transect of the peritoneal cavities） by injection using a #7 piercing needle. The fetal development was observed and miscarriage rate was noted. The level ofchimerism obtained in the fetal goats was studied at set intervals. Results Human hematopoitic stem cells were injected into 49 goat recipients under sonographic guidance, obtaining 36 live born goats with miscarriage rate （26.7%, 13/49） similar to those from the uninjected control group, but significantly lower than the laparatomy group （63%）. Conclusions The method described herein is efficient and safe, with much lowered miscarriage risk comparing to that using surgical interventions for delivering stem cells into fetal goats, and is suitable for producing large numbers of chimeras with many useful applications including serving as animal models for studying stem cell biology in a live organism.