Changes Of ANGPTL2,3and Related Inflammation Factor Expressions In Mastitis Mice

Objective:Mastitis is a common inflammatory disease in female. The infected breast tissue is red, swelling, painful, and warm along with a dip in milk supply. It leads to remarkably decreases in milk production, which brings domestic farmers huge economic losses and seriously affects on the growth of the national economy. Nowadays, the etiology and mechanism of mastitis is unclear. Angiopoietin-like protein2(ANGPTL2) is a new secreted glycoprotein that was discovered and named by kim in2000. Recent research has shown that ANGPTL2may be a key pro-inflammatory factor. As mentioned above, mastitis is a common inflammatory disease of breast. Therefore, we hypothesized that the gene expression of ANGPTL2is correlated with inflammation of mastitis mice. Moreover, inflammation is related with hyperlipidemia. Angiopoietin-like protein3(ANGPTL3) contributes to hyperlipidemia. Therefore, we hypothesized that mastitis results in hyperlipidemia, which is related with elevated ANGPTL3expression in mastitis mice. In the present study, we detected the mRNA expressions of ANGPTL2, ANGPTL3and related inflammation factor, and blood lipids in mastitis mice, then explored the relationship between ANGPTL2and mastitis related inflammation factor, between ANGPTL3and blood lipid level. It provided new strategies for the prevention and treatment of mastitis, and new ideas for the relationship between inflammation and hyperlipidemia.Methods:1) Mastitis mouse model.20lactating mice,5-7days after birth of the offspring, were randomly divided into two groups:blank control group (physiological saline) and challenged group (Staphylococcus aureus mastitis model). By observing the clinical characters of mastitis mouse, mammary tissues were dissected and isolated for analysis of histopathological examination by bacteria counting and HE staining.2) Analysis the mRNA expression levels of ANGPTL2and related inflammation factors. Relative quantitative PCR of fluorescence was performed to quantify the mRNA expressions of ANGPTL2, tumor necrosis factor-a (TNF-a), and interleukin (IL)-6by using the2-△△CT method.3) Analysis the expression level of ANGPTL3mRNA and lipid levels. Relative quantitative PCR of fluorescence was performed to quantify the expressions of ANGPTL3mRNA. Biochemical methods were performed to check the levels of plasma triglyceride (TG), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C). Results:1) The present results showed that compared with blank control group, the mammary tissue of mastitis mice was red, swelling along with a dip in milk supply. Mastitis mice were less sensitive to environment. The structure of mammary gland was destroyed completely with large areas of cell fragments in challenged group at24h after Staphylococcus aureus infusion.2)The present results showed that compared with blank control group, ANGTL2, TNF-a, and IL-6mRNA expressions were clearly augmented in mastitis murine (P<0.01). Pearson’s correlation analysis showed a significantly positive linear correlation between ANGPTL2mRNA expression and TNF-a mRNA in mastitis mice (r=0.695, P=0.008); the ANGPTL2mRNA expression positively correlated with the IL-6mRNA (r=0.725, P=0.009).3) The present results showed that compared with blank control group, ANGPTL3mRNA expression quantified by2-△△CT method was obviously increased in mastitis mice (P<0.01). Plasma TG, LDL-C, and TC concentrations were also significantly elevated in mastitis mice compared with control mice.Conclusion:The present results suggest that that elevated ANGPTL2expression may be correlated with inflammation of mastitis mice. Increased ANGPTL3expression is related to hyperlipidemia in mastitis mice.