A study on the variation of cytokine and electrolyte levels in rhesus macaques, cynomolgus monkeys, and Assamese macaques

Background: Non-human primates (NPHs), such as rhesus macaques, cynomolgus monkeys, and Assamese macaques, play a crucial role in biomedical research. However, baseline cytokine and electrolyte data for these three species, particularly data stratified by age and sex, are limited. Therefore, the aim of this study was to establish and analyze age- and sex-specific cytokine and electrolyte profiles in these three species.

Methods: This study included 40 rhesus macaques (21 males, 19 females), 33 cynomolgus monkeys (17 males, 16 females), and 45 Assamese macaques (25 males, 20 females) classified by age (1-5 years, 6-12 years, >13 years) and sex. The levels of 23 immune function indicators and 5 electrolyte indicators were measured.

Results: Among the three monkey species, the levels of sCD40L, IL-18, MCP-1, MIP-1β, TGFa, K⁺, Na⁺, and Cl^- exhibited species-, sex-, and age-related differences. Comparison within the same species，sex had no significant impact on cytokine levels in NHPs but did affect electrolyte levels, particularly Cl^- and Na⁺ levels, in cynomolgus monkeys and Assamese macaques. Electrolyte levels in NHPs were not affected by age, whereas the levels of certain cytokines, particularly sCD40L, GM-CSF, and IL-10, varied with age. The remaining 21 cytokines demonstrated no significant age-related changes.

Conclusions: Significant variations in cytokine and electrolyte levels exist among different monkey species, sexes, and age groups. This research provides valuable resources for NHP researchers and sets the stage for further exploring the impacts of sex and age on NHP physiology and immune function.