The present study aimed to evaluate the protective effects of emodin on cyclophosphamide (CY)-induced oxidative injury in peripheral blood leukocytes (PBLs) of blunt snout bream and the potential mechanisms. We examined the cell viability, lactate dehydrogenase (LDH) release, apoptosis, mitochondrial membrane potential (Δѱm), reactive oxygen species (ROS) generation and correlative gene expression of nuclear factor-erythroid 2 related factor-2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) signaling molecules. For the control group, PBLs were maintained in normal cell culture medium for 12 h. For the CY group, cells were exposed to 0.32 mg/mL CY for 6 h, followed by maintaining in RPMI-1640 complete medium for an additional 6 h. Cells in the CY + Emodin group were exposed to 0.32 mg/mL CY for 6 h, and then exposed to 0.20 μg/mL emodin for 6 h. We observed that emodin significantly inhibited CY-induced apoptosis in PBLs through increasing cell viability and decreasing LDH release. Emodin also inhibited Δѱm disruption and respiratory burst in CY-induced PBLs. In consistent with these results, emodin attenuated oxidative stress in CY-induced PBLs by significantly upregulating Nrf2, BTB and CNC homolog 1 (Bach1), superoxide dismutase (SOD) and catalase (CAT) genes while significantly downregulates Keap1 in Nrf2-Keap1 signaling pathway. These results collectively demonstrate that emodin can alleviate CY-induced oxidative stress in the PBLs of blunt snout bream, possibly through activating Nrf2-Keap1 signaling pathway. Our findings also suggest that emodin might be developed as a promising therapeutic agent for treating oxidative injury in blunt snout bream.

本研究旨在评估大黄素对环磷酰胺（CY）诱导的钝吻鲷外周血白细胞（PBLs）氧化损伤的保护作用及其潜在机制。我们检查了细胞活力、乳酸脱氢酶 (LDH) 释放、细胞凋亡、线粒体膜电位 ( Δѱm)、核因子-类红细胞 2 相关因子-2 (Nrf2)-Kelch 样 ECH 相关蛋白 1 (Keap1) 信号分子的活性氧 (ROS) 生成和相关基因表达。对于对照组，PBLs 在正常细胞培养基中维持 12 小时。对于 CY 组，细胞暴露于 0.32 mg/mL CY 6 小时，然后在 RPMI-1640 完全培养基中再维持 6 小时。CY + Emodin 组细胞暴露于 0.32 mg/mL CY 6 h，然后暴露于 0.20 μg/mL 大黄素 6 h。我们观察到大黄素通过增加细胞活力和减少 LDH 释放显着抑制 PBLs 中 CY 诱导的细胞凋亡。大黄素也抑制ΔѱmCY 诱导的 PBL 中的中断和呼吸爆发。与这些结果一致，大黄素通过显着上调Nrf2、BTB 和 CNC 同源物 1 ( Bach1 )、超氧化物歧化酶 ( SOD ) 和过氧化氢酶 ( CAT ) 基因，同时显着下调Nrf2-Keap1 信号通路中的Keap1来减弱 CY 诱导的 PBL 中的氧化应激. 这些结果共同表明，大黄素可以减轻钝吻鲷 PBLs 中 CY 诱导的氧化应激，可能是通过激活 Nrf2-Keap1 信号通路。我们的研究结果还表明，大黄素可能被开发为一种有前途的治疗钝吻鲷氧化损伤的治疗剂。