Study On Influence And Mechanism Of Ablactation Rats’ Zinc Supplementation To Adulthood Obesity

Obejective: The aim of this study was to investigated the effects of different dose of zinc supplementation in early after ablactation on later-life obesity and the underlying mechanisms. Methods: Eighty-five male Sprague-Dawley rats were weaned on d 21,received a basic diet(BD) or different dose of zinc supplement diets(H-Zn, M-Zn, L-Zn)for four weeks. Following one week of basic diet, then the BD control group was divided into high-fat diet(HFD) control group and normal control group. Afterward, normal control group fed with BD and H-Zn, M-Zn, L-Zn group and HFD control group fed with HFD for eight weeks to induce obesity. Food intake was recorded daily and body weight was measured weekly. On 5, 13 weeks, the body fat content, serum lipid, blood glucose and the levels of leptin and insulin were detected. We took livers and kidneys for pathological sthdies by HE dyeing. On 13 weeks the UCP2, UCP3 and GLUT4 gene expression levels were detected by RT-PCR technique. Results: 1. After zinc supplementation, the body weigh of M-Zn group was lower than other groups. After obesity induction, there was no statistically significant difference of Lee indexs between normal control group and the H-Zn group and M-Zn group. The body weight, body fat content,and Lee index of HFD control group was higher than other groups. 2. After zinc supplementation, the serum leptin of M-Zn, L-Zn group was lower vs. BD control group.After obesity induction, the blood glucose, total cholesterol and triglyceride of HFD control group were higher than other groups and the High density lipoprotein cholesterol of it was lower than normal control group. 3. After zinc supplementation, the serum leptin and insulin of three zinc supplementation groups were higher than BD control group.After obesity induction, the serum leptin and insulin of HFD control group were higher than other groups. 4. The levels of UCP2, UCP3 and GLUT4 gene expression of HFD control group was lower than other goups obviously. The levels of UCP2, UCP3 andGLUT4 gene expression of M-Zn were higher than normal control group, M-Zn and L-Zn group. Conclusion: The result suggested that moderate zinc supplementation in early after ablactation may reduce later obese risk by keeping the normal levels of body fat content and Lee index, persistently influencing synthesis and secretion of leptin and insulin,permanently regulating of UCP2, UCP3 and GLUT4 gene expressions when they were exposed to HFD in later life.