高浓度日粮诱导的山羊结肠上皮损伤可被超营养硒水平通过减轻氧化应激和细胞凋亡最小化。
Supranutritional selenium level minimizes high concentrate diet-induced epithelial injury by alleviating oxidative stress and apoptosis in colon of goat.
机构信息
Department Veterinary Physiology and Biochemistry, Sindh Agricultural University, 70060, Tando Jam, Pakistan.
Department of Veterinary Parasitology, Sindh Agricultural University, 70060, Tandojam, Pakistan.
出版信息
BMC Vet Res. 2020 Nov 27;16(1):462. doi: 10.1186/s12917-020-02653-4.
BACKGROUND
High concentrate (HC) diet-induced oxidative stress causes gut epithelial damages associated with apoptosis. Selenium (Se) being an integral component of glutathione peroxidase (GSH-Px) plays an important role in antioxidant defense system. Therefore, increasing dietary Se level would alleviate HC diet-induced injuries in gut mucosa. The present study investigated eighteen cross-bred goats, randomly divided into three groups (n = 6/group) fed either low concentrate (LC, roughage: concentrate ratio 65:35), high concentrate (HC, 35:65) or HC plus Se (HC-SY) diets for 10 weeks. Se was supplemented at the dose rate of 0.5 mg Se kg diet in the form of selenium yeast. The background Se level in HC and LC diets were 0.15 and 0.035 mg.kg diet, respectively. The Se at the dose of 0.115 mg.kg diet was added in LC diet to make its concentration equivalent to HC diet and with the supplementation of 0.5 mg Se kg, the goats in group HC-SY received total Se by 0.65 mg.kg diet.
RESULTS
The molar concentrations of individual and total short chain fatty acids (TSCFA) significantly increased (P < 0.05) with simultaneous decrease in pH of colonic fluid in goats of HC and HC-SY groups compared with LC goats. HC diet induced loss of epithelial integrity, inflammation and loss of goblet cells in colonic mucosa associated with higher lipopolysaccharide (LPS) concentrations in colonic fluid whereas, the addition of SY in HC diet alleviated such damaging changes. Compared with LC, the HC diet elevated malondialdehyde (MDA) level with concurrent decrease in GSH-Px and superoxide dismutase (SOD) activities, while SY supplementation attenuated these changes and improved antioxidant status in colonic epithelium. Moreover, epithelial injury and oxidative stress in colon of HC goats were associated with increased apoptosis as evidenced by downregulation of bcl2 and upregulation of bax, caspases 3 and 8 mRNA expressions compared with LC goats. On contrary, addition of SY in HC (HC-SY) diet alleviated these changes by modulating expression of apoptotic genes in colonic epithelium.
CONCLUSIONS
Our data suggest that supranutritional level of Se attenuates HC diet-induced oxidative stress and apoptosis and thereby minimizes the epithelial injury in colon of goats.
背景
高浓度（HC）饮食引起的氧化应激会导致与细胞凋亡相关的肠道上皮损伤。硒（Se）是谷胱甘肽过氧化物酶（GSH-Px）的组成部分，在抗氧化防御系统中发挥重要作用。因此，增加膳食硒水平可以减轻 HC 饮食引起的肠道黏膜损伤。本研究选用 18 只杂交羊，随机分为三组（每组 6 只），分别饲喂低浓度（LC，粗饲料：精料比例为 65:35）、高浓度（HC，35:65）或高浓度加硒（HC-SY）饲料 10 周。硒以酵母硒的形式以 0.5mgSe/kg 日粮的剂量添加。HC 和 LC 日粮的基础硒水平分别为 0.15 和 0.035mg.kg 日粮，LC 日粮中添加 0.115mg.kg 日粮的硒，使其浓度与 HC 日粮相当，添加 0.5mg Se/kg，HC-SY 组的山羊通过 0.65mg.kg 日粮获得总硒。
结果
与 LC 组相比，HC 和 HC-SY 组的短链脂肪酸（TSCFA）摩尔浓度显著增加（P<0.05），同时结肠液 pH 值降低。HC 饮食导致结肠黏膜上皮完整性丧失、炎症和杯状细胞丢失，与结肠液中更高的脂多糖（LPS）浓度有关，而 SY 在 HC 饮食中的添加减轻了这种损伤。与 LC 相比，HC 饮食提高了丙二醛（MDA）水平，同时降低了 GSH-Px 和超氧化物歧化酶（SOD）的活性，而 SY 补充剂减轻了这些变化，改善了结肠上皮的抗氧化状态。此外，HC 组山羊的上皮损伤和氧化应激与细胞凋亡增加有关，与 LC 组相比，bcl2 下调，bax、caspase 3 和 caspase 8mRNA 表达上调。相反，在 HC（HC-SY）饮食中添加 SY 通过调节结肠上皮细胞凋亡基因的表达来减轻这些变化。
结论
我们的数据表明，超营养水平的硒可减轻 HC 饮食引起的氧化应激和细胞凋亡，从而最大限度地减少山羊结肠的上皮损伤。
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