The Effect Of Adipose Tissue-specific Knockout Of IGFALS Gene On Glucose And Lipid Metabolism In Mice

Insulin-like growth factor acid-labile subunit(IGFALS)is mainly synthesized in the liver,and its process can be regulated by growth hormone(GH).Studies have shown that the main function of IGFALS is through the insulin-like growth factor-1(IGF-1)and insulin-like growth factor binding protein-3(IGFBP-3).A ternary complex is formed to stabilize the half-life of IGF-I in serum.Insulin-like growth factors IGF-1and IGF-2 are involved in a variety of cell proliferation,apoptosis and differentiation;they also promote glucose metabolism and transport in adipose tissue,and promote fat and glycogen synthesis.As a key component of the ternary complex,IGFALS can ensure the biological activity of IGFs by extending the half-life of IGFs from 10 minutes in the free form to 30-90 minutes in the binary complex to more than 12 hours in combination with the ternary complex.However,the specific function of IGFALS in adipose tissue has not been reported.In this study,IGFALS-Flox mice constructed on the basis of Cre-Loxp technology in the laboratory were used to construct a mouse model of adipose tissue-specific knockout IGFALS gene(AdALSKO)by hybridization with Adipoq-Cre mice.Phenotypes were analyzed.At the same time,combined with high-fat diet induction,by comparing the physiological metabolic phenotype differences of the mouse model under different dietary conditions,the effects of IGFALS gene on lipid metabolism in mice were explored.The aim of this study was to reveal the effect of IGFALS gene on the morphology and function of adipose tissue under the combined effect of IGFALS gene deletion and environmental factors.Mouse models(AdALSKO)were obtained by hybridization of Adipo-Cre tool mice with IGFALS-Flox mice,and mouse genotypes were identified by PCR.Feeding and monitoring the body weight of the normal diet(RC),preliminary analysis of physiological metabolic phenotypic changes in the AdALSKO mouse model;further high-fat(HF)feeding of AdALSKO mice and Flox mice for 16 weeks,monitoring the body weight of the mice,and Glucose tolerance test(GTT)and insulin tolerance test(ITT)were performed at 8 weeks of HF feeding(12 weeks old mice)and 16 weeks(20weeks old mice),followed by dissection and organ weight analysis;The serum levels of GH and IGF-1 in serum were detected by ELISA and enzyme-labeled colorimetric assay.The effects of IGFALS gene deletion on the adipose tissue and liver morphology of mice were analyzed by H&E staining and oil red O staining.The expression of lipid metabolism related genes(such as Acc,Fas,Hsl,Atgl,Mgl,etc.)in white adipose tissue was analyzed by RT-PCR;the level of lipolytic enzyme(such as ATGL)in white adipose tissue was detected by Western Blot.In summary,this study successfully constructed a novel adipose tissue-specific knockout IGFALS gene mouse model AdALSKO using Cre-LoxP technology.The mice were able to survive and multiply normally,and no significant abnormalities were observed in the overall appearance phenotype.Under normal dietary conditions,there was no significant difference in body weight and tissue organ weight between AdALSKO mice and control mice.Under high-fat co-administration conditions,AdALSKO mice are more likely to develop diet-induced obesity,with worse glucose tolerance and marked insulin resistance.Knocking out the Als gene in adipose tissue promotes lipid accumulation in subcutaneous fat by promoting lipid synthesis and inhibiting lipid breakdown.However,there is no significant effect on liver lipid metabolism,and further research will provide new ideas for the prevention and treatment of obesity.