| Objective: Though observing changes in serum lipids,liver and fat tissue markers,and gene expression of lipid metabolism,such as PPARs,after observing DEHP exposure in pubertal rats of both normal diet and high-fat diet,it is clear influence that DEHP affects lipid metabolism in pubertal rats.The focus is exploring the possible mechanism of DEHP lipid metabolism disorder,providing scientific basis for the prevention and treatment of lipid metabolism disorders.Methods: 160 healthy Wistar rats were selected,male and female,with a 21-day age and body weight of 50-60 g.After one week’s the standard animal house was raised,they were randomly divided into two groups: normal diet group and high-fat diet group.Give ordinary feed and high fat feed separately.Each group was randomly divided into four groups: control group(corn oil)and low-dose DEHP group(5mg/kg/d,1/6000LD50),medium-dose DEHP group(50mg/kg/d,1/ 600LD50),high dose DEHP exposure group(500mg/kg/d,1/60LD50),each group of 20,in the early morning gavage,continuous exposure to the drug for 8 weeks.Record daily water intake,food intake,and body weight.After the end of the exposure,blood was collected to separate sera and visceral fat and liver were taken.The levels of TC,TG,LDL and HDL in blood lipids were measured by automatic biochemical analyzer;ADP and LEP were measured by enzyme-linked immunosorbent assay(ELISA);histopathological changes in liver were observed by HE staining;and TC in fat and liver were determined by ELISA.TG content;RT-PCR,immunohistochemistry,Western-Blot method to determine m RNA and protein levels of lipid metabolism control genes in liver and adipose tissue.SPSS24.0 software was used for statistical analysis.The measurement data were expressed as x±s.One-way analysis of variance(One Way ANOVA)was used to compare multiple groups.Between the two groups,the SNK test(Student-Newman-Keuls method)or the Kruskal-Wallis test was used.The test standard was α=0.05.Results: 1.There was no significant difference in the body weight between the normal diet group and the control group(P>0.05).The body weight of the 500 mg/kg/d group at the 5th to 8th week was significantly higher than that of the other groups,and the difference was significant.(P<0.05).There was no statistically significant difference in body weight between high-fat diet rats exposed to 1,2,3,and 5 weeks and the control group(P>0.05).The body weight of 500 mg/kg/d DEHP-exposed rats was significantly higher than that of the control at the 4th week.There was a significant difference between the 50 mg/kg/d group and the 50 mg/kg/d group(P<0.05);The body weight of the 500 mg/kg/d 500 mg/kg/d group increased significantly compared with other groups at the 6th and 8th week(P<0.05);The body weight of 500 mg/kg/d group was significantly increased compared with the control group(P<0.05).At the 3rd,4th,6th,7th,and 8th weeks,rats in the 500 mg/kg/d diet group had lower body weight than the same-dose high-fat diet rats(P<0.05).2.Food intake in the second and seventh week: 500 mg/kg/d dose was greater than other dose groups(P<0.05);Week 3: Control and 50 mg/kg/d doses were less than 500 mg/kg/ d dose group(P<0.05);Week 5、8: 50 mg/kg/d dose group less than 500 mg/kg/d dose group(P<0.05);Week 6: 5 mg/kg/d dose group and 50 mg/ In the kg/d dose group,the food intake was less than 500mg/kg/d dose group,the difference was statistically significant(P<0.05).The dietary intake of 500 mg/kg/d in the seventh week of rats with high-fat diet was significantly higher than that in the 50 mg/kg/d group(P<0.05),and 500 mg/kg/d in the third,fifth,sixth,and eighth weeks.There was a significant difference between the group and the control group,the 5 mg/kg/d dose group,and the 50 mg/kg/d dose group(P<0.05).There was no significant difference in the amount of dietary food in the rest of the week.Comparing the dietary intake of the same dose group with that of the high-fat diet,it was found that,except for the 500 mg/kg/d dose group,the rats in the third week of normal diet consumed less food than the normal diet rats,and the other dose groups consumed The rats were weighed in excess of normal diet(P<0.05).In the third week of normal diet rats,the water intake of the 500 mg/kg/d dose group was significantly higher than that of the 50 mg/kg/d dose group(P<0.05).In the high-fat diet rats,the water intake of the 500 mg/kg/d dose group at the fifth and seventhweek was significantly higher than that of the other groups(P<0.05).There was no statistically significant difference between the same diet group and the rats fed with high-fat diet(P>0.05).3.The liver organ coefficient of the rats was statistically analyzed.The results showed that the viscera coefficient of the 500 mg/kg/d exposure group significantly increased compared with other groups in the normal diet and high fat diet rats,and the difference was statistically significant(P<0.05).The results of the comparison of the same dose group of rats with normal diet and high-fat diet showed that the hepatic index of rats fed high-fat diet 500 mg/kg/d was significantly higher than that of normal diet rats(P<0.05).4.In normal diet and high-fat diet rats,serum TC levels in DEHP-treated group were significantly higher than those in control group(P<0.05).Serum TG levels in DEHP-treated group were significantly higher than those in control group.In the normal diet and high-fat diet rats,serum HDL levels in the DEHP-treated group were significantly higher than those in the control group(P<0.05).There was no significant difference in serum LDL levels between dietary rats(P>0.05).After comparing the same diet with the high-fat diet rat in the same dose group,there was no significant difference in serum TC,TG,HDL,and LDL levels(P>0.05).5.In normal diet and high-fat diet rats,the serum ADP level in the DEHP group was significantly higher than that in the control group(P<0.05).In high-fat diet rats,serum LEP levels in the 500 mg/kg/d and 50 mg/kg/d groups were significantly higher than those in the 5 mg/kg/d group(P<0.05).The comparison of serum LEP levels in rats with the same dose of normal diet and high-fat diet found that the serum ADP content in the control group was higher than that in the normal diet rats,and the high-fat diet rats were given 5 mg/kg/d serum.The content of LEP was significantly higher than that of normal diet rats(P<0.05).6.The analysis of TC and TG contents in liver tissue of rats in each dose group showed that there was no statistically significant difference in TC and TG levels between livers in normal diet and high fat diet rats(P<0.05).However,comparisons of serum TC and TG levels in liver tissue of rats with the same dose of normal diet and high-fat diet found that the rats in the control group,the 5 mg/kg/d dose group,and the 50 mg/kg/d dose group had normal liver TC,The level of TG was higher in rats fed with high fat diet(P<0.05).7.The analysis of TC and TG contents in adipose tissue of rats in each dose group showed that the TC content of adipose tissue in DEHP-treated group was significantly higher than that in the control group(P<0.05).The content of TG in adipose tissue of 500 mg/kg/d high-fat diet rats was significantly lower than that of other dose groups(P<0.05).Comparing the TC and TG contents of serum adipose tissue in rats with the same dose of normal diet and high-fat diet,it was found that the levels of TC and TG in adipose tissue of DEHP-treated group were lower than those in rats fed with high fat diet,and the differences were statistically significant.Significance(P<0.05).8.Liver histomorphological observations revealed that no histological abnormalities were observed in the liver tissue of the normal diet control group.All rats given a high-fat diet had hepatic steatosis to varying degrees,and some DEHP-treated groups showed mild inflammation,hepatocyte edema was evident,and some cells were broken.9.The levels of PPARα,SREBP-1c,ACC,FAS,ACOX m RNA and protein in hepatic lipid metabolism were significantly higher in the DEHP group than in the control group(P<0.05).The results of pairwise comparison of the above genes in the same dose group of normal diet and high fat diet rats showed that the levels of PPARα,SREBP-1c,ACC,FAS and ACOX m RNA were higher in the high fat diet rats than in the normal diet(P<0.05).).10.The levels of PPARγ and LPL m RNA were significantly higher in DEHP group than in the control group,but the m RNA level of HSL was significantly lower than that of the control group(P<0.05).On the protein level,the level of PPARγ in the DEHP exposure dose group was significantly higher than that in the control group,and the difference was statistically significant;the difference in LPL protein level between the DEHP exposure dose group and the control group was not statistically significant(P>0.05).The level of HSL protein in the DEHP exposure group was lower than that in the control group(P<0.05).The results of pairwise comparison of the above genes in normal diet and high-fat diet rats in the same dose group showed that the m RNA levels of PPARγ and LPL in the high-fat diet rats were generally higher than those in the diet group,while the HSL m RNA levels in the high-fat diet rats were generally higher than those in the normal diet group.Ordinary diet rats.Conclusion: 1.Exposure to DEHP and a high-fat diet may increase body weight in adolescent rats.2.DEHP poisoning can lead to elevated serum levels of TC and HDL in adolescent rats with high-fat diet and normal diet;it can also lead to elevated serum TG levels in high-fat diet rats.This suggests that exposure to DEHP may lead to lipid metabolism disorders in high-fat diets and adolescent rats with normal diets,and high-fat diets may increase lipid metabolism disorders.3.Exposure to DEHP and high-fat diet may increase liver volume and increase liver volume,and up-regulate the expression of PPARα and SREBP-1c,ACOX,FAS,and ACC genes.The mechanism may be through up-regulation of PPARα and SREBP-1c to increase their downstream target genes.The expression of ACOX,FAS,and ACC affects the lipid metabolism in the liver.4.DEHP exposure and high-fat diet can destroy the balance of ADP and LEP secreted by rat adipose tissue.Exposure to DEHP resulted in increased expression of PPARγ and LPL and decreased expression of HSL.The mechanism may be up-regulation of PPARγ to increase the expression of LPL,decrease the expression of HSL,and affect the lipid breakdown and oxidation of adipose tissue.However,large doses of DEHP also affect the translation process of LPL,resulting in decreased expression of LPL protein,which weakens its role in promoting lipid oxidation. |
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