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Updated: Aug 8, 2026
Isolation and Characterization of Neutrophils with Anti-Tumor Properties
Published on: June 19, 2015
Inhibition of tumor growth by L-deprenyl involves neural-immune interactions in rats with spontaneously developing
S Thyagarajan1, K S Madden, S Y Stevens
1Center for Neuroimmunology, Loma Linda University School of Medicine, CA 92350, USA. sthyagarajan@som.llu.edu
Abstract:
L-deprenyl, a monoamine oxidase-B inhibitor, has been shown to reverse the age-related decline in sympathetic noradrenergic innervation and immune function in old rats and enhance T cell and NK cell activity in tumor-bearing rats. The objective of the present study was to examine whether deprenyl treatment of old female rats with mammary tumors could augment sympathetic nervous system and immune responses to inhibit the tumor growth. Female Sprague-Dawley rats with spontaneous mammary tumors were administered 0, 2.5 mg, or 5.0 mg/kg body weight (BW)/day deprenyl for i.p. 9 weeks. Tumor diameter, tumor number and body weight were measured throughout the treatment period. At the end of the treatment period, norepinephrine (NE) concentration, interferon-gamma production (IFN-gamma), Con A-induced T lymphocyte proliferation, and percentage of T and B lymphocytes and natural killer cells were measured in the spleen, and the concentrations of monoamines were measured in the medial basal hypothalamus. Relative to saline-treated controls, treatment with deprenyl reduced tumor growth, increased NE concentration, IFN-gamma production and percentage of the CD8+ T lymphocytes in the spleen. In the medial basal hypothalamus, deprenyl treatment increased the concentrations of catecholamines and indoleamine. These results suggest that the anti-tumor effects of deprenyl on spontaneous rat mammary tumors may be achieved via neural-immune signaling in the spleen and medial basal hypothalamus.
Insights
L-deprenyl treatment reduced mammary tumor growth in old rats by enhancing sympathetic nervous system and immune responses. This suggests deprenyl
Area of Science:
- Neuroscience
- Immunology
- Oncology
Background:
- L-deprenyl, a monoamine oxidase-B inhibitor, can reverse age-related declines in sympathetic innervation and immune function.
- Previous studies show L-deprenyl enhances T cell and NK cell activity in tumor-bearing rats.
Purpose of the Study:
- To investigate if L-deprenyl treatment augments sympathetic nervous system and immune responses to inhibit mammary tumor growth in old female rats.
Main Methods:
- Female Sprague-Dawley rats with spontaneous mammary tumors received daily intraperitoneal injections of L-deprenyl (0, 2.5, or 5.0 mg/kg BW) for 9 weeks.
- Tumor growth, body weight, spleen immune markers (norepinephrine, IFN-gamma, T lymphocyte proliferation, T/B/NK cell percentages), and medial basal hypothalamus monoamine concentrations were measured.
Main Results:
- L-deprenyl treatment significantly reduced tumor diameter and number compared to controls.
- Deprenyl increased splenic norepinephrine concentration, IFN-gamma production, and CD8+ T lymphocyte percentage.
- Medial basal hypothalamus catecholamine and indoleamine concentrations were elevated by deprenyl treatment.
Conclusions:
- L-deprenyl exhibits anti-tumor effects on spontaneous rat mammary tumors.
- These effects are likely mediated through neural-immune signaling pathways involving the spleen and medial basal hypothalamus.
