Cyclic erythropoiesis in the S1/S1d mouse

Area of Science:

• Hematology
• Animal Models
• Radiobiology

Background:

• Congenital anemia in mice can lead to complex hematological responses.
• Strontium-89 (89Sr) is a radioisotope that can impact hematopoietic processes.
• Previous studies indicated oscillating hematocrit values in W/Wv mice after 89Sr administration.

Purpose of the Study:

• To investigate cyclic erythropoiesis in a second strain of congenitally anemic mice (S1/S1d).
• To determine the role of the spleen in spontaneous and 89Sr-induced cyclic erythropoiesis.

Main Methods:

• Administration of 0.5 microCi 89Sr/g body weight to S1/S1d mice.
• Monitoring hematocrit and reticulocyte levels to assess red blood cell cycling.
• Investigating spontaneous cycling in untreated mice.
• Evaluating the effect of splenectomy before and after 89Sr treatment.

Main Results:

• S1/S1d mice showed significant hematocrit fluctuations (nadir 13%, zenith 37%) and reticulocyte cycling (low 3%, high 40%) after 89Sr exposure.
• Spontaneous hematocrit cycling was observed in a subset of untreated S1/S1d mice.
• Low-dose 89Sr combined with phlebotomy also induced substantial cyclic erythropoiesis.
• Splenectomy abolished both spontaneous and 89Sr-induced cyclic erythropoiesis in S1/S1d mice.

Conclusions:

• The spleen is essential for both spontaneous and radiostrontium-induced cyclic erythropoiesis in S1/S1d mice.
• These findings elucidate the spleen's regulatory role in red blood cell production dynamics in anemic models.