Activation of whole body by high levels of polyamine intake in rats

Abstract

Polyamines are important to the survival and activation of organs and tissues via a homeostatic cell-metabolic process, and the polyamine content in cytoplasm decreases with aging. Decreases in cellular polyamine have been known to augment mutagenesis and cell death. Thus, supplementary polyamine in food is important to the prevention of aging. Here we show the anti-aging effects of oral intake of polyamine using luciferase-transgenic rats. Healthy rats, 10-12 weeks old, were given foods containing 0.01% and 0.1% (w/w) of polyamine, as compared a control food without polyamine, for 4 weeks. Using a bioimaging system, the photon intensities seen in the whole bodies and livers of rats consuming 0.1% of polyamine in food were stronger than those in rats consuming 0.01% and 0% of polyamine. However, there were no differences between groups in other characteristics, such as liver damage and body weight. In conclusion, we found that polyamine intake can activate cells throughout the whole body, providing an anti-aging effect.

Keywords: Anti-aging; Living imaging; Oral intake; Polyamine; Transgenic rat.

Fig. 1

Analysis of the conditions of rats consuming the test foods (n = 6 each). a Daily intake of 10-week-old Luc-Tg rats. There was no change in intake amounts due to changes in polyamine content. b Furthermore, there was no weight change. The black bar indicates 0% of polyamine in food, the gray bar indicates 0.01% of polyamine, and the white bar indicates 0.1% of polyamine

Fig. 2

Changes in photon intensity based on intake of polyamine (n = 6 each). a Kinetics of photon intensity levels over several weeks. b The value of the photon intensity at the 0th week was set to 100%. c In the bar graph, each groups’ values are shown at 0, 1, 2, 3, and 4 weeks from left to right. The food with 0.01% polyamine has the same polyamine content as normal commercial foods

Fig. 3

Photon images of rat livers based on polyamine intake (n = 6 each). a After 4 weeks of oral intake, the rats’ whole livers were removed using by IVIS. b Photon intensity values are shown for rats consuming 0%, 0.01%, and 0.1% of polyamine in food. Photon levels of rats consuming foods with 0% and 0.01% of polyamine were significantly lower than those of rats consuming 0.1% of polyamine in food (P < 0.01). c The polyamine concentrations of rat livers were examined in each experimental group using high-pressure liquid chromatography. The black bar indicates 0% of polyamine in food, the gray bar indicates 0.01% of polyamine, and the white bar indicates 0.1% of polyamine (P < 0.01)

Fig. 4

Analysis of serum and pathological specimens. a Serum levels of aspartate aminotransferase and alanine transaminase are shown at 0–4 weeks of oral intake of foods with polyamine (n = 6 each). The black bar indicates 0% of polyamine in food, the gray bar indicates 0.01% of polyamine, and the white bar indicates 0.1% of polyamine. Representative b hematoxylin and eosin–stained and c Ki-67-stained sections of liver. Arrows indicate Ki-67-positive cells of hepatocytes. Original magnification × 100. Scale bars, 200 µm