| Objective:To observe the effect of Exendin-4intervention on the protein and mRNA expression of HO-1, NT in type2diabetic nephropathy(DN) rats renal tissues, and give an insight into the mechanism of oxidative stress whether involved in the protection of DN rats renal tissues by Exendin-4intervention.Methods:1. Experimental design:Established rat model of DN by high-sugar and high-fat diet combined with streptozotocin (40mg/kg). The successful model rats were randomly divided into DN group, low-dosage group and high-dosage group, and compared with normal rats. Low-dosage(4μg/kg·d) of Exendin-4were given to low dosage intervention group, high-dosage(20μg/kgd·) of Exendin-4were given to high dosage intervention group, and continuous administration of six weeks. Immunohistochemistry was used to observe the changes of HO-1and NT protein expression, RT-PCR was used to observe the changes of HO-1and NT mRNA expression.2. Statistical analysis:Used One-Way ANOVA with multiple comparisons to study the changes of HO-1protein and mRNA expression among four groups.Results:1. Rat general conditions:Normal rats were freely accessed to food and water. DN rats presented spiritual malaise, decreased activity and weight loss.2. Immunohistochemistry staining:HO-1protein were obviously expressed in the tubules of normal group, low-dosage intervention group and high-dosage intervention group, but weakly or hardly expressed in DN group. The average gray value were: normal group (11.0±2.2), DN group (0.5±0.1), low-dosage treatment group (2.7±0.6), high-dosage treatment group (6.5±1.3). The expression of HO-1protein among the four groups showed significant differences (F=99.2, P<0.001). NT protein were slightly expressed in the tubules of normal group, low-dosage intervention group and high-dosage intervention group, but obviously expressed in DN group. The average gray value were:normal group (0.5±0.1), DN group (5.9±1.7), low-dosage treatment group (2.9±0.5), high-dosage treatment group (1.7±0.3). The expression of NT protein among the four groups showed significant differences (F=55.4, P0.001).3. RT-PCR method:HO-1mRNA were highly expressed in normal group and high-dosage intervention group, and the values were nearly approached; weakly or hardly expressed in DN group, and the expression quantity increased by the intervention of Exendin-4. The2-△△CT values were:normal group (32.1±5.4), DN group (4.1±0.7), low-dosage group (7.9±0.9), high-dosage group (33.0±6.3). The expression of HO-1mRNA among the four groups showed significant differences (F=110.8, P<0.001). NT mRNA were slightly expressed in normal group, obviously expressed in DN group, and the expression quantity significantly decreased by the intervention of Exendin-4. The2-△△CT values were:normal group (1.0±0.2), DN group (10.4±1.6), low-dosage group (6.1±1.5), high-dosage group (3.2±0.6). The expression of NT mRNA among the four groups showed significant differences (F=104.3, P<0.001).Conclusion:1. DN retrograded the expression of HO-1in rat renal tissue, and significantly improved by Exendin-4intervention. DN strengthened the expression of NT in rat renal tissue, and significantly reduced by Exendin-4intervention. 2. Oxidative stress mechanisms may be involved in the protection effect of Exendin-4on rat kidney under DN condintions. |
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