| Aim To investigate the effect of nutritional excess in lactation on the metabolism of cholesterol in adult mouse,and to explore the regularity of cholesterol metabolism gene expression by establishing a lactation-deficient mouse model.Method The lactation overnutrition model was established by adjusting the number of parental breastfeeding offspring.Removing the female and keepping male after the mices were born in 5th day.The male mices by weight were randomly divided into two group.One group is form of 3 mices,which we called small litter(SL group)designed as an experimental group.SL group was designed as an experimental group.The other group is form of 10 mices,which we called normal litter(NL group)designed as a normal control group.After breastfeeding to3 th week,all mices of SL group and NL group were weaned and right now given ordinary feed until 9th week.We ended one part of the experiment Including 10 mices of NL group and 9 mices of SL group and then collectted SL group and NL group mouses blood and liver.SL group was not grouped and also given ordinary feed until we finished this part experiment.The remaining mices of NL group were grouped again.NL group was grouped to two group.One group still was given ordinary feed called NL group.NL group was designed as a normal control group.The other group was given high fat feed,which we called high fat litter(HF group).HF group was designed as a positive control group.At the 13 th and 17 th week,the changes of the corresponding indexes of mice were observed.The treatment of mouse blood and liver is as follows:Serum was obtained from blood by centrifugation.And then we examined the concentration of the following molecules in serum: total triglycerides(TG),total cholesterol(TC),3-hydroxy-3-methyl glutaryl coenzyme A reductase(HMG-Co AR),cholesterol7-alpha hydroxylase(CYP7A1).The liver was divided into the following sections:1 We took a big piece of liver and put it into frozen tube.After kelp in liquid nitrogen for 10 min,the tube was transferred to-80 ? refrigerator.The liver would be used to examined the expression level of m RNA and protein of gene as follow: liver X receptor alpha(LXR-?),peroxisome proliferator-activated receptor alpha(PPAR-?),ATP binding cassette transporter A1(ABCA1),ATP binding cassette transporter G1(ABCG1),3-hydroxy-3-methyl glutaryl coenzyme A reductase(HMG-Co AR).2 We took the edge of the liver and put it in 4%formaldehyde solution for fixation.And then,the liver would be made into pathological sections.3 We weighed 0.2g liver and made it into homogenate with1 ml Physiological saline.After homogenate centrifuged,we collected supernatant.And then,we would examined the concentration of the following molecules:HMG-Co AR,CYP7A1 and total protein.The concentration of HMG-Co AR and CYP7A1 would be divided by the concentration of total protein for standardization.Result 1 In 3th week,SL group had higher body weight than NL group,and the difference between the two groups was statistically significant(p <0.05).SL group had higher length of body than NL group,and the difference between the two groups was statistically significant(p <0.05).2 In 9th week,The weight and liver index of SL group were higher than those of NL group,and the difference between the two groups was statistically significant(p <0.05).The serum TC of SL group was higher than that of NL group,the difference was statistically significant(p <0.05).The content of HMG-Co AR in the supernatant of liver homogenate in SL group was higher than that in NL group,and the difference was statistically significant(p<0.05).The m RNA and protein expression levels of ABCA1,ABCG1,HMG-Co AR,LXR-? and PPAR-? genes were not found the difference in mice liver.3 In 13 th week,The liver index of SL group was lower than that of HF group,and the difference was statistically significant(p<0.05).The serum TG of NL group was higher than that of HF group,and the difference was statistically significant(p<0.05).The serum HMG-Co AR in SL group was lower than that in NL group,and the difference was statistically significant(p <0.05).The serum CYP7A1 of SL group was higher than that of NL group,and the difference was statistically significant(p <0.05).The HMG-Co AR in the liver homogenate supernatant of SL group was higher than that of NL group,and the difference was statistically significant(p <0.05).The levels of CYP7A1 in the supernatant of liver homogenate of SL group were higher than those of NL group and HF group,and the difference was statistically significant(p <0.05).The m RNA and protein expression levels of ABCA1,ABCG1,HMG-Co AR,LXR-?,PPAR-? genes in mice liver were not found the difference.4.In 17 th week,The liver index and fasting blood glucose of HF group were higher than those of SL group and NL group,and the difference was statistically significant(p <0.05).The serum TC of SL group was lower than that of HF group,and the difference was statistically significant(p <0.05).The serum CYP7A1 in NL group was higher than that in HF group,and the difference was statistically significant(p <0.05).The serum CYP7A1 of SL group was lower than that of NL group,and the difference was statistically significant(p <0.05).The expression level of ABCA1 gene m RNA in NL group was lower than that in HF group,and the difference was statistically significant(p <0.05).The expression level of LXR-?gene m RNA in NL group was lower than that in HF group,and the difference was statistically significant(p <0.05).The expression level of LXR-? gene m RNA in SL group was significantly higher than that in NL group,and the difference was statistically significant(p <0.05).The expression of PPAR-? m RNA in SL group was higher than that in NL group and HF group,and the difference was statistically significant(p <0.05).The expression level of ABCG1 protein in NL group was lower than that in HF group,and the difference was statistically significant(p<0.05).The expression of LXR-? protein in SL group was significantly lower than that in NL group,and the difference was statistically significant(p <0.05).The expression level of PPAR-? protein in NL group was lower than that in HF group,and the difference was statistically significant(p <0.05).The expression of PPAR-? protein in SL group was significantly higher than that in NL group and HF group,and the difference was statistically significant(p <0.05).Conclusion 1 Nutritional excess in lactation can cause hepatic cholesterol synthesis capacity increased,while increasing its hepatic metabolism of cholesterol to bile acids in adult mice.2 Adult mice was nutritional excess in lactation that may have high expression of LXR-? and PPAR-? m RNA in liver.PPAR-? protein is highly expressed in liver.And the expression of LXR-? protein is in a low level. |
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