| Objective:By establishing a Type 2 diabetic(T2D)rat model,we observed rat's changes in body weight,fasting blood glucose,changes in biochemical parameters,pathological changes in the kidneys,and the expression of p-JNK and Caspase-12 protein related to endoplasmic reticulum stress(ERS)in the renal to explore the possible mechanism of liraglutide on renal protection in T2 D rats.Methods:After thirty SD rats(male)first feeded adaptively in the animal house of Shanxi Provincial People's Hospital for seven days,six of them were randomly selected as normal control groups(NC group)and fed conventional fodder.while the remaining 24 rats were used as type 2 diabetic models and the feed was given high-sugar high-fat diet for one month.After one month,the rats fasted(need to ensure drinking water)for 12 hours,and the rats were weighed to calculate the dose of streptozotocin(STZ)(at 40 mg/kg),and 24 rats were injected into citric acid from the abdomen(STZ diluted with sodium citrate)and6 normal control rats were injected with equal doses of citric acid/sodium citrate.Three days after the injection of STZ,the tail of the sterilized rat was bled and the blood glucose was greater than or equal to 16.7 mmol/L,which is considered that the model was successfully prepared.The rats successfully established in the modeling group were randomly divided into three groups: diabetic control group(DMC group),liraglutide100ug/kg intervention group(LIR-L group),Liraglutide 200ug/kg intervention group(LIR-H group).After the grouping is completed LIR-L group and LIR-H group began subcutaneous injection of norotense(liraglutide)once daily for 8 weeks,whose doses were respectively 100ug/kg and 200ug/kg;the NC group and DMC group were injected with the same dose of saline.At the end of the experiment,the body weight of the rats was measured and the blood glucose of the rats was recorded,the 24-hour urine volume wasused to measure the urine related indexe and the blood was collected to detect the blood lipids,fasting insulin,and renal function.Pathological sections were prepared by conventional(HE)and special(PAS)two different staining methods to observe the structural changes of kidney tissue in each group of rats.Immunohistochemistry was used to analyze the relative expression of p-JNK and Caspase-12 protein in the kidney of each group.Results:1.General description of experimental ratsAfter successful modeling,the diabetic rats were inactive,the rats had rough hair and lack of brightness,and even had hair loss,the rat urine volume increased.Compared to the normal group,the number of dunnages was significantly increased and the dunnages smell was odorous,and its humidity was increased.Rats in the normal group were full of energy,active,and gained weight.At the end of the experiment,25 rats in 30 rats successfully completed the experiment:Diabetes control group 7,the remaining three groups of 6 each.Five of the deaths may be due to complications caused by hyperglycemia.2.The body weight and fasting blood glucose of rats in each group at the end of 8 weeks after drug intervention(1)Body weight change: Compared with the weight of the NC group rats(477.17±23.82g),the DMC group(396.51±9.15g)the body weights was decreased(P<0.05).Compared with the DMC group,the body weights of the LIR-L group(440.02±34.22g)and the LIR-H group(434.67±39.42g)both increased(P<0.05).There was no difference in body weight between the LIR-L group and LIR-H group(P>0.05).(2)Changes of fasting blood glucose: Compared with fasting blood glucose(4.58±0.69 mmol/L)in NC group,DMC group(22.57±1.42mmol/L)fasting blood glucose increased(P<0.05).Compared with DMC group,fasting blood glucose in LIR-L group(19.43±1.07mmol/L)and LIR-H group(17.32±1.02mmol/L)were all decreased(P<0.05).Comparison of Fasting Blood Glucose between LIR-L and LIR-H Group Rats,LIR-H group decreased significantly(P <0.05).3.Four groups of rat biochemical indicators after the end of experimental intervention(1)Blood biochemical indicators: Compared with the NC group,the total cholesterol,serum creatinine,urea nitrogen,and fasting insulin indexes in the DMC group increased(P<0.05),while the triglyceride,low-density lipoprotein,and high-density lipoprotein indexes did not Difference(P>0.05).Compared with rats in DMC group,the indexes of total cholesterol,serum creatinine,urea nitrogen,and fasting insulin in LIR-L group and LIR-H group were all decreased(P<0.05),while there was no difference in triglyceride,low-density lipoprotein,and high-density lipoprotein(P>0.05).The serum creatinine,urea nitrogen and fasting insulin levels in LIR-H group were lower than those in LIR-L group(P<0.05),however,there was no difference between the four lipids in the LIR-H group and the LIR-L group(P>0.05).(2)Urine examination index: Compared with the NC group,the 24-hour urinary protein,urinary microalbuminuria,microalbumin/urine/creatinine index in the DMC group all increased(P<0.05).Compared with rats in DMC group,all three indicators of LIR-L and LIR-H groups decreased(P<0.05),and the LIR-H group had a decrease in these three indicators compared with the LIR-L group(P<0.05).4.Pathological changes of kidney in each groupThe results of HE staining and PAS special staining microscopy showed that the morphology and structure of the kidneys in the NC group were basically normal.The size of the glomeruli in the DMC group increased,the structure was disordered,the matrix outside the mesangium was increased,and the basement membrane thickened.Compared with DMC groups,the renal pathological changes of rats in the LIR-L and LIR-H groups were reduced.5.Immunohistochemistry detection of p-JNK and Caspase-12 protein expression in the kidney and relative quantitative resultsAccording to the immunohistochemistry reagents,the tan area positive expression area was introduced.Under light microscope,p-JNK protein was more expressed in glomeruli than in renal tubules;Caspase-12 protein was more expressed in renal tubules,and some glomeruli were also expressed,and the expression was relatively low.In the NC group,the expression of p-JNK and Caspase-12 in the glomerulus and renal tubules was low.The expression of p-JNK and Caspase-12 protein in kidneys of DMC group was significantly higher than that of NC group(P<0.05).After intervention with liraglutide,theexpression of the above two proteins in LIR-L and LIR-H groups were decresed than DMC in the kidney(P<0.05).however,there was no significant difference between the LIR-L group and LIR-H group in the expression the above two proteins(P>0.05).Conclusion:1.The expression of p-JNK and Caspase-12 protein in the kidney of DMC rats was significantly increased,which confirmed the ERS activation in the kidneys of T2 D rats.2.Liraglutide reduced the expression of p-JNK and Caspase-12 protein in kidneys of T2 D rats and relieved the worsening of renal function,which suggests that liraglutide may protect kidney by inhibiting ERS. |
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