[Effects of Porphyra yezoensis extract on hepatic inflammatory factors and oxidative stress in type 1 diabetic mice]

Abstract

Objective: To study the effect of Porphyra yezoensis extract on liver inflammation and oxidative stress in type 1 diabetics mice.

Methods: A total of ninety-one C57 BL/6 J male mice were adaptively fed for two weeks, and twelve C57 BL/6 J male mice were randomly reserved to be included in the blank control group. The rest of the mice were fasted overnight for twelve hours(except water), and they were given 170.00 mg/kg streptozotocin by intraperitoneal injection. Fasting blood glucose in type 1 diabetics mice were greater than or equal to 16.7 mmol/L after seven days, and polydipsia, polyphagia, polyuria and weight loss appeared, which were judged to be the successful model of type 1 diabetes. Forty-eight successfully modeled mice were divided into the model control group, the low dose of Porphyra yezoensis extract group, the medium dose of Porphyra yezoensis extract and high dose of Porphyra yezoensis extract group according to the fasting blood glucose and body weight. The mice in the blank control group and the model group were given the same amount of normal saline. The low-dose, medium-dose, and high-dose intervention groups were separately given the corresponding dose of Porphyra yezoensis extract by intragastric administration for six weeks. The body weight of type 1 diabetic mice, changes in body length, fasting blood glucose, insulin, liver inflammatory factors and oxidative stress indicators and pathological sections of liver and pancreas after the intervention of Porphyra yezoensis extract were observed. The glucose oxidase method was used to determine the fasting blood glucose level of type 1 diabetic mice. The serum insulin content, liver inflammatory factor levels and oxidative stress indicators were detected by the enzyme-linked immunosorbent assay(ELISA). The hematoxylin-eosin staining method was used to observe histopathology of liver and pancreas paraffin sections.

Results: The weight of the model control group was significantly lower than that of the blank control group(P<0.05), and the fasting blood glucose value was significantly higher than that of the blank control group(P<0.05). There was no statistical difference. In terms of inflammatory factors, compared with the model control group, low-dose Porphyra yezoensis extract can increase serum insulin levels and reduce liver tumor necrosis factor-α(TNF-α) levels(P<0.05) in T1DM mice, and medium-dose Porphyra yezoensis extract can reduce liver TNF-α level(P<0.05), high-dose Porphyra yezoensis extract can reduce the level of interleukin-1β(IL-1β)(P<0.05). The histopathological conditions of pancreas in different intervention groups were improved compared with the model control group, and the number of β cells increased compared with the model group. In terms of oxidative stress, compared with the model control group, low-dose Porphyra yezoensis extract can significantly reduce the levels of liver alanine aminotransferase(ALT) and malondialdehyde(MDA)(P<0.05), and high-dose Porphyra yezoensis extract can significantly increase the levels of glutathione peroxidase(GSH-Px) and catalase(CAT)(P<0.05).

Conclusion: The protective effect of Porphyra yezoensis extract on liver oxidative damage in T1DM mice may be achieved by regulating the activity of CAT and GSH-Px and reducing the content of MDA. In addition, Porphyra yezoensis extract can reduce liver TNF-α and IL-1β levels to improve liver inflammation.

Keywords: Porphyra yezoensis; liver inflammation; mice; oxidative stress; type 1 diabetes.