Abstract:

The purpose of this study is to investigate the effects of sheep milk and goat milk on the liver and kidney of type 2 diabetic mice, and provide theoretical reference for clinical prevention and treatment of diabetes and its complications. Dairy analyzer was used to detect the nutritional components of sheep milk and goat milk. The type 2 diabetes mellitus(T2DM) mouse models were induced by high-sugar and high-fat diet combined with streptozotocin (STZ, STZ injection was conducted in week 5). The diabetic mice were randomly divided into diabetes model control (DMC) group, sheep milk group (Sheep) and goat milk group (Goat) with 10 mice in each group. A control group (Con) was also set up. Mice in Sheep group and Goat group were fed sheep milk and goat milk respectively from the first week until the end of the ninth week, and the body weight of mice and their food intake were measured every week. Glucose tolerance of mice was measured at the end of the 4th and 9th week. At the end of the 9th week, blood and urine were collected from mice, and the levels of blood lipids, blood urea nitrogen, serum creatinine, urinary albumin, and urinary creatinine were determined. Using Real time-PCR to test the expression abundance of mRNA of IL-6, TNF-α, IL-1β and TGF-β1 in the liver and kidneys. It was found that the fat, protein, lactose and total solid content of sheep milk were significantly higher than those of goat milk (P < 0.01) based on dairy analyzer analysis. Before the injection of STZ, the body weight of DMC mice at week 2 to week 4 increased significantly compared with the Con group (P < 0.01). At the 3rd and 4th week, the body weight of mice in Sheep group decreased significantly compared with DMC group (P < 0.01). After STZ injection, the body weight of DMC mice decreased significantly (P < 0.05) compored with Con group. However, at the end of the 9th week, compared with the DMC group, the weight loss rate of mice in Sheep group slowed down significantly (P < 0.01). In the glucose tolerance test, it was found that the area under the glucose tolerance test curve of mice in Sheep and Goat groups decreased significantly compared with the DMC group (P < 0.05) at the end of the 9th week. Analysis of serum and urine samples showed that the blood lipid levels and urine albumin levels of mice in Sheep and Goat groups tended to decrease compared with the DMC group, but there was no significant difference (P>0.05). However, the serum urea nitrogen and blood creatinine levels, as well as the urine creatinine level, decreased significantly (P < 0.05). In addition, the HE staining results showed that sheep and goat milk could alleviate liver steatosis, glomerular lesions and renal tubular epithelial cell vacuolar degeneration in diabetic mice. Compared with the DMC group, the mRNA content of IL-6, TNF-α, IL-1β, and TGF-β1 in the liver and kidneys of the Sheep group mice showed a significant decrease, while in the Goat group mice, the content of other inflammatory factors also significantly decreased, except the TNF-α of kidney. In conclusion, sheep milk and goat milk can significantly inhibit the intake of T2DM mice, delay the weight loss of diabetic mice, improve glucose tolerance as well as effectively reduce the histopathological damage of liver and kidney, significantly inhibit the inflammation of liver and kidney, and play an effective role in the treatment of diabetes mellitus and its complications, and the mitigating effect of sheep milk is better than that of goat milk.

Key words: goat milk, sheep milk, diabetes, liver, kidney