Study On The Relationship Between Diet And Gallbladder Wall Macrophages And Cholesterol Diseases In Hamsters

Objective:Different dietary interventions were given to Syrian golden hamsters to explore the relationship among diet,gallbladder wall macrophages and gallbladder cholesterol diseases.Methods:Fifty healthy male Syrian golden hamsters were selected and fed adaptively for 2weeks.They were randomly divided into 5 groups:basic blank control group(BBC group),8-week high-fat diet experimental group(8w HE group),16-week normal low fat diet control group(16w LC group),16-week high-fat diet control group(16w HC group)and 8-week high fat to 8-week normal low fat diet experimental group(8w H-8w LE group).The rats in BBC group were killed after measuring their body weight and were not fed;8w HE group was fed with high-fat diet for 8 weeks;The16w LC group was fed low fat diet(normal basal diet)for 16 weeks;16w HC group was fed with high-fat diet for 16 weeks;The 8w H-8w LE group was first fed with high fat feed for 8 weeks,and then fed with low fat feed(normal basal feed)for 8 weeks.During the feeding period,the body weight,fur glossiness,mental status and activity of hamsters in each group were observed and recorded every week.After feeding,the hamsters were given forbidden water for 12 hours,and the blood was collected from the medial canthus vein of the hamster eyeball.After neck dislocation,the specimens of liver and gallbladder were taken,the morphology and texture were observed,the lithogenesis was recorded,and the gallbladder tissue was fixed by paraformaldehyde.Using automatic biochemical analyzer to detect four levels of blood lipids in hamsters in each group;Qualitative detection of stone composition by Fourier transform infrared spectroscopy;Detection of lipid accumulation in gallbladder wall by oil red o staining;Detection of CD68 expression and distribution in gallbladder wall by immunohistochemical staining;The staining results were quantified by IPP software;The above experimental results were statistically analyzed using SPSS software.The data between the BBC group and the 8w HE group were analyzed using t-tests,while the data between the other three groups were analyzed using one-way ANOVA.Results:1.General situation:There were no significant differences in the mental state,activity,food intake,fur glossiness,and initial weight of each group of hamsters;After 8 weeks of feeding,the weight of the 8w HE group increased compared to the BBC group(P<0.01);After 16 weeks of feeding,the weight of the 16w HC group increased compared to the 8w H-8w LE group and the 16w LC group(P<0.01).2.Four blood lipid levels:The blood lipid levels in the 8w HE group were higher than those in the BBC group(P<0.01);The four levels of blood lipids in the 16w HC group were higher than those in the 16w LC group and the 8w H-8w LE group(P<0.01),but the HDL-c levels in the 8w H-8w LE group were higher than those in the other two groups(P<0.01);The 8w H-8w LE group showed an increase compared to the 16w LC group(P<0.01),but there was no significant difference in plasma triglyceride levels between the two groups(P>0.05).3.Liver and gallbladder morphology and texture:The BBC group and 16w LC group had normal liver appearance,red color,soft texture,thin and transparent gallbladder wall,and no obvious stone formation was observed;The feeding group(8w HE group,16w HC group,and 8w H-8w LE group)that received high-fat diet intervention showed liver appearance swelling,blunt and thick liver margin,obvious fatty change,tough texture,thick gallbladder wall,and yellow white color.Some gallstones were visible in some gallstones,with stone formation rates of 50%,70%,and 40%,respectively.The stones were qualitatively detected as cholesterol by infrared spectroscopy.4.Oil red o staining:There was no significant accumulation of lipid substances in the gallbladder wall tissue of the BBC group and the 16w LC group;The lipid substances in the gallbladder wall tissue of the 8w HE group,16w HC group,and8w H-8w LE group all gathered in the subepithelial layer.The average optical density value of the 8w HE group was higher than that of the BBC group(P<0.01);The16w HC group showed an increase compared to the 16w LC group and the 8w H-8w LE group(P<0.01);The 8w H-8w LE group showed an increase compared to the 16w LC group(P<0.01).5.CD68 immunohistochemistry:There was no significant expression of CD68~+cells in the gallbladder wall tissue of the BBC group and the 16w LC group.The CD68~+cells in the gallbladder wall tissue of the 8w HE group,16w HC group,and8w H-8w LE group were all expressed in the subepithelial layer.The average optical density value of the 8w HE group was higher than that of the BBC group(P<0.01);The 16w HC group showed an increase compared to the 16w LC group and the8w H-8w LE group(P<0.01);The 8w H-8w LE group showed an increase compared to the 16w LC group(P<0.01).Conclusion:1.Feeding high fat feed to hamsters can significantly increase their blood lipid levels,significantly aggregate lipid substances in the gallbladder wall,and provide sufficient cholesterol pool environment for cholesterol transport in the gallbladder wall MC,promoting MC expression.Early intervention with normal basic low fat feed can reduce this cholesterol pool and inhibit MC expression.2.MC participates in the reverse transport of cholesterol in the gallbladder wall tissue of hamsters.In the early stages of a high-fat diet,MC plays a protective role in the gallbladder.With the continuous intervention of a high-fat diet,the large aggregation of MC after phagocytosis of lipids may be another pathogenic factor that hinders the normal progression of gallbladder function and the formation of GCD.3.Early intervention with a normal basal low-fat diet on a high-fat diet can increase the ratio of HDL-c to LDL-c,promote the reverse transport of cholesterol in the gallbladder wall tissue,significantly reduce the accumulation of lipid substances and the expression of MC in the gallbladder wall,and reduce the rate of gallstone formation.This may be another way to prevent GCD.