<b>Polysaccharide of </b><b><i>Atractylodes Macrocephala</i></b><b> Koidz alleviates Cyclophosphamide induced lymphocytes injury</b><b> in goslings</b>

The immune system of gosling is not fully developed, making them susceptible to pathogens, stress, and adverse environmental factors, which can lead to compromised immune function. Cyclophosphamide (<b>CTX)</b> is a commonly used immunosuppressive agent, causing DNA strand breaks and cell death, thereby inducing lymphocytes injury and reducing immune function. This study aimed to evaluate whether polysaccharide from <i>Atractylodes macrocephala</i> Koidz (<b>PAMK</b>) can alleviate CTX-induced lymphocyte injury in goslings and to elucidate its underlying mechanisms. One-day-old Magang goslings were divided into control, CTX, PAMK, and PAMK+CTX groups. Thymus morphology, lymphocyte apoptosis, cytokine/chemokine expression, and transcriptome profiles were assessed through histology, TUNEL staining, flow cytometry, RT-qPCR, and Western blot. CCL5 overexpression experiments were conducted in vitro to further validate the mechanistic pathway. PAMK significantly alleviated CTX-induced thymic damage, preserved thymocyte structure, and reduced lymphocyte apoptosis. Transcriptome and KEGG analyses revealed the chemokine signaling pathway as a key target. PAMK downregulated CCL5/CCR5 expression and restored downstream Src, PI3K, Raf, and ERK1/2 activity. In CCL5-overexpressing lymphocytes, PAMK reversed pro-apoptotic effects by modulating the same pathway, confirming its regulatory role. PAMK mitigates CTX-induced thymic injury in goslings by modulating the CCL5/CCR5-mediated chemokine signaling pathway, offering potential for developing immunomodulatory strategies in poultry.

雏鹅的免疫系统尚未发育完全，易受病原体、应激及不良环境因素侵袭，进而导致免疫功能受损。环磷酰胺（Cyclophosphamide, CTX）是一种常用免疫抑制剂，可引发DNA链断裂与细胞死亡，诱导淋巴细胞损伤并降低免疫功能。本研究旨在评估白术（Atractylodes macrocephala Koidz）多糖（PAMK）是否能够缓解环磷酰胺诱导的雏鹅淋巴细胞损伤，并阐明其潜在作用机制。选取1日龄马冈雏鹅，分为对照组、CTX模型组、PAMK单独给药组以及PAMK+CTX联合给药组。通过组织学观察、TUNEL染色、流式细胞术、实时定量聚合酶链反应（RT-qPCR）、蛋白质印迹（Western blot）等技术，对胸腺形态、淋巴细胞凋亡情况、细胞因子/趋化因子表达水平以及转录组图谱进行分析。体外开展CCL5过表达实验，以进一步验证其潜在作用通路。实验结果显示，PAMK可显著缓解环磷酰胺诱导的胸腺损伤，维持胸腺细胞结构完整性，并降低淋巴细胞凋亡率。转录组测序及京都基因与基因组百科全书（KEGG）富集分析表明，趋化因子信号通路为PAMK发挥调控作用的关键靶点。PAMK可下调CCL5/CCR5的表达水平，并恢复下游Src、PI3K、Raf及ERK1/2的信号活性。在CCL5过表达的淋巴细胞中，PAMK可通过调控该通路逆转促凋亡效应，证实了其对该信号轴的调控作用。综上，PAMK可通过调控CCL5/CCR5介导的趋化因子信号通路，缓解环磷酰胺诱导的雏鹅胸腺损伤，为禽类免疫调控策略的开发提供了潜在应用方向。