Abstract：
Heat stress reduces the number of Sertoli cells, which is closely related to an imbalanced redox status. Glutamate functions to maintain the equilibrium of redox homeostasis. However, the role of glutamate in heat treated Sertoli cells remains unclear. Herein, Sertoli cells from 3-week-old piglets were treated at 44 °C for 30 min (heat stress). Glutamate levels increased significantly following heat stress treatment, followed by a gradual decrease during recovery, while glutathione (GSH) showed a gradual increase. The addition of exogenous glutamate (700 μM) to Sertoli cells before heat stress significantly reduced the heat stress-induced apoptosis rate, mediated by enhanced levels of antioxidant substances (superoxide dismutase (SOD), total antioxidant capacity (TAC), and GSH) and reduced levels of oxidative substances (reactive oxygen species (ROS) and malondialdehyde (MDA)). Glutamate addition to Sertoli cells before heat stress upregulated the levels of glutamate-cysteine ligase, modifier subunit (Gclm), glutathione synthetase (Gss), thioredoxin (Trx1) and B-cell leukemia/lymphoma 2 (Bcl-2), and the ratio of phosphorylated Akt (protein kinase B)/total Akt. However, it decreased the levels of Bcl2-associated X protein (Bax) and cleaved-caspase 3. Addition of the inhibitor of glutaminase (Gls1), Bptes (Bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl)ethyl sulfide, 30 μM)to Sertoli cells before heat stress reversed these effects. These results inferred that glutamate rescued heat stress-induced apoptosis in Sertoli cells by enhancing activity of antioxidant enzymes and activating the Trx1-Akt pathway. Thus, glutamate supplementation might represent a novel strategy to alleviate the negative effect of heat stress.
摘要：
热应激减少支持细胞的数量，这与不平衡的氧化还原状态密切相关。谷氨酸的功能是维持氧化还原稳态的平衡。然而,谷氨酸在热处理的支持细胞中的作用尚不清楚。在这里，将来自3周龄仔猪的支持细胞在44°C下处理30分钟(热应激)。热应激治疗后谷氨酸水平显著增加，随后在恢复期间逐渐减少，而谷胱甘肽（GSH）则呈逐渐增加的趋势。热应激前在支持细胞中添加外源谷氨酸（700μM）显着降低了热应激诱导的凋亡率，通过提高抗氧化物质水平(超氧化物歧化酶(SOD)，总抗氧化能力(TAC)，和GSH）和降低的氧化物质水平（活性氧（ROS）和丙二醛（MDA））。在热应激之前向支持细胞中添加谷氨酸会上调谷氨酸-半胱氨酸连接酶的水平，修饰亚基（Gclm），谷胱甘肽合成酶(Gss),硫氧还蛋白（Trx1）和B细胞白血病/淋巴瘤2（Bcl-2），和磷酸化Akt(蛋白激酶B)/总Akt的比率。然而,它降低了Bcl2相关X蛋白（Bax）和calved-caspase3的水平。添加谷氨酰胺酶抑制剂（Gls1），Bptes（双-2-（5-苯基乙酰氨基-1,3,4-噻二唑-2-基）乙基硫醚，30μM）在热应激逆转这些作用之前对支持细胞进行治疗。这些结果推断，谷氨酸通过增强抗氧化酶的活性和激活Trx1-Akt途径来挽救热应激诱导的支持细胞凋亡。因此，补充谷氨酸可能是一种缓解热应激负面影响的新策略。
