Peromyscus leucopus mice: a potential animal model for haematological studies

Peromyscus leucopus mice share physical similarities with laboratory mice Mus musculus (MM) but have higher agility and longer lifespan. We compared domesticated P. leucopus linville (PLL) and M. musculus C57BL/6 (MMB6) mice for cellular composition of peripheral blood (PB), bone marrow (BM) and spleen. PLL mice had significantly fewer platelets and significantly more monocytes in the blood, and notably fewer megakaryocytes in the BM. Spleens of PLL mice were significantly smaller, with 50% fewer cells and reduced 'red pulp'. There was no obvious haematological change in PLL mice between 2-8 and 16-26 months of age, except for a significant increase in blood monocytes. Cellular reactive oxygen species (ROS) content showed no change with age but differed significantly between different cell types. Treating two to eight month-old PLL mice with antioxidant N-acetylcysteine in drinking water for three months did not affect cellular ROS content, but increased blood leucocytes especially the concentration of monocytes. The low platelets, low megakaryocytes, high monocytes and low splenic erythropoiesis in PLL mice resemble human measurements better than the values seen in MMB6.