Inoue T, Hirabayashi Y, Kanisawa M, Mitsui H, Taniguchi S, Yoshida K
Department of Pathology, Yokohoama City University School of Medicine, Japan.
J Comp Pathol. 1994 Feb;110(2):195-205. doi: 10.1016/s0021-9975(08)80190-9.
Regulation of spleen-colony formation, a clonal assay for haemopoietic stem cells, is very different in mice and rats. In the rat, there is an involution of the colony-forming ability of the spleen during infantile development, whereas in mice the ability is maintained throughout life. In our re-evaluation of endogenous spleen colony formation in rats after graded doses of total-body irradiation, colonies ceased to appear after 12 weeks of age. However, histological sections showed that there were tiny colonies growing in the spleen, even at 20 weeks. These microscopical colonies developed into visible colonies when the rats were given treatments that increased the haemopoietic requirement. Thus, the amount of 59FeCl3 incorporated into the spleen increased to compensate for a decrease in uptake by the bone marrow. Rats in which bone-marrow activity was inhibited by 89SrCl2, showed extensive colony formation in the spleen, even after 12 weeks of age, when the endogenous colonies were induced by a sublethal dose of radiation. About twice as much 59Fe acetate activity was incorporated into the spleens of the experimental animals than in those of control rats. These findings imply that spleen-colony formation responds to the haemopoietic requirement of the spleen rather than that of the bone marrow. Furthermore, the requirement of the spleen seems to be much smaller in rats than in mice, because bone-marrow capacity for haemopoiesis is relatively larger in rats.
脾集落形成是一种造血干细胞的克隆检测方法，其在小鼠和大鼠中的调控方式差异很大。在大鼠中，脾脏的集落形成能力在幼年发育过程中会出现退化，而在小鼠中这种能力则终生维持。在我们对全身分次照射后大鼠内源性脾集落形成的重新评估中，12周龄后集落不再出现。然而，组织学切片显示，即使在20周龄时，脾脏中仍有微小集落在生长。当给大鼠进行增加造血需求的处理时，这些显微镜下的集落会发展成可见集落。因此，掺入脾脏的59FeCl3量增加，以补偿骨髓摄取量的减少。用89SrCl2抑制骨髓活性的大鼠，即使在12周龄后，当用亚致死剂量辐射诱导内源性集落时，脾脏中也会出现大量集落形成。实验动物脾脏中掺入的59Fe乙酸盐活性约是对照大鼠的两倍。这些发现表明，脾集落形成对脾脏而非骨髓的造血需求作出反应。此外，大鼠脾脏的需求似乎比小鼠小得多，因为大鼠的骨髓造血能力相对较大。
