Research on Collagen Peptides as Food Additives for Regulating Immune Function During Spaceflight

During space missions, multiple adverse factors including weightlessness and space radiation severely impair astronauts’ physical health, prominently manifested as declined immune function[2]. As a critical defensive barrier of the organism, the immune system resists the invasion of pathogenic microorganisms and eliminates tumour cells, meanwhile playing an indispensable role in maintaining internal environmental homeostasis of the body.

Existing studies have verified that spaceflight suppresses both innate and adaptive immunity in organisms[3-5], and the microgravity environment constitutes one of the core contributors to astronauts’ compromised immune function.

Collagen peptides are mixtures of polypeptides produced via enzymatic hydrolysis of collagen or gelatin, rich in essential amino acids for humans such as glycine, proline and hydroxyproline. They have been applied as food additives to alleviate joint disorders and improve skin conditions[6-7]. Additional research demonstrates that collagen peptides facilitate the differentiation of murine CD4⁺ T lymphocytes and restrain the onset of allergic reactions[8].

Preliminary work by our research team has confirmed that collagen peptides reverse immunosuppression induced by glucocorticoids and simulated weightlessness in mice[9-10]. Nevertheless, whether collagen peptides exert direct regulatory effects on microgravity-mediated functional inhibition of T lymphocytes remains unclear, which is the core research objective of the present study.

1. Experimental Methods

Murine splenocytes were isolated, and a rotating cell culture system was adopted to simulate the microgravity environment. T lymphocytes were stimulated with the mitogen concanavalin A (ConA), followed by treatment with collagen peptides at varying concentrations. The proliferative capacity of lymphocytes and cytokine concentrations in cell culture supernatants were subsequently determined.

2. Research Results

T lymphocytes perform diversified biological functions ranging from eliminating infected target cells to secreting signaling molecules that recruit other immune cells to initiate immune responses, serving as pivotal executors of adaptive immunity. Proper immune responses rely on normal activation of T cells; insufficient T cell activation inevitably leads to defective immune reactions[11].

ConA, a typical mitogen, can specifically trigger T lymphocyte activation, and ConA-induced proliferation of mouse splenocytes is a reliable indicator of T cell activation and bioactivity to a certain extent[12].The regulatory effect of collagen peptides on the proliferation of murine splenic T lymphocytes cultured under simulated microgravity is presented in the attached figure.

Cytokines act as key signaling mediators for immune cell functioning, participating extensively in the modulation of immune cell proliferation, differentiation, chemotaxis, adhesion, immune recognition and apoptosis. Th1/Th2 cytokines occupy a vital position in balancing cellular and humoral immunity.

Consistent with domestic and international published findings, our data indicated that under simulated microgravity, the elevation amplitude of cytokine secretion from ConA-activated splenic T lymphocytes was markedly lower compared with cells cultured under normal gravitational conditions.The modulatory impacts of collagen peptides on Th1/Th2 cytokine production by murine splenic T lymphocytes under simulated microgravity are summarized in the attached table.

Previous investigations reported that collagen peptides boost T lymphocyte proliferation[13], mitigate thymus and spleen atrophy triggered by ultraviolet irradiation in mice[14], elevate peripheral erythrocyte and leukocyte counts, and promote hematopoietic function[15].Data regarding the influence of collagen peptides on growth factor secretion from murine splenic T lymphocytes cultured under simulated microgravity are listed in the corresponding table.

Our experimental outcomes revealed that collagen peptides barely alter the proliferation and cytokine secretion of splenic T cells under conventional culture settings. In contrast, collagen peptide supplementation significantly enhances lymphocyte proliferation and cytokine release under simulated microgravity, thereby alleviating microgravity-induced functional suppression of T lymphocytes. Cytokine modulation is presumed to be a key pathway underlying the immunoregulatory property of collagen peptides, whereas the detailed molecular mechanism requires further in-depth exploration.

3. Discussion and Analysis

Experimental results confirm that simulated microgravity inhibits the proliferative potential of splenic T lymphocytes and reduces their cytokine secretion, while collagen peptides effectively reverse such suppression by facilitating lymphocyte proliferation and cytokine synthesis under microgravity simulation.

Conclusion: Collagen peptides relieve microgravity-induced T lymphocyte dysfunction via regulating lymphocyte proliferation and cytokine secretion.

In summary, collagen peptides can partially counteract the inhibitory effects of simulated microgravity on T lymphocytes. Featuring non-toxicity and negligible side effects as nutritional supplements, collagen peptides possess promising potential to be developed into food additives for immune regulation during spaceflight.

References

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