Objective To investigate the regulatory effects of Sitagliptin on autophagy related protein in type 2 diabetic mellitus (T2DM ) rats . Methods T2DM rat model was established by feeding with high-fat diet and giving low-dose of streptozotocin 45 mg/kg intraperitoneally .After modeling ,the rats were randomly divided into three groups :intragastric administration of 10 mg/kg sitagliptin (SGT group) ,intragastric administration of PBS (T2DM group) and intraperitoneal injection of 10 IU/(kg · d) insulin (ISL group ) .Normal rats treated with PBS were set as normal controls (NC group) .12 weeks later ,blood specimens of the rats were collected and tested .HE and Masson's trichrome staining were performed on hepatic tissue .RT-PCR method was performed to detect the expressing level of autophagy-related genes ,including ATG3 ,ATG12 ,Beclin1 and p62.Semiquantitative Western blot was performed to detect the protein levels of target genes ,including LC3B . Results After 12 weeks of treatment ,the blood glucose of SGT group was lower than that of T2DM group (P<0.05) .HE and Masson staining showed that the degree of hepatic fibrosis was improved in the SGT group .Compared with NC group ,autophagy-related genes in liver tissue of T2DM rats did not change much .The mRNA expression levels of ATG3 ,ATG12 ,p62 and Beclin1 in the T2DM group were (0.82 ± 0.12) ,(0.66 ± 0.03) ,(0.12 ± 0.01) and (0.52 ± 0.02 ) ,respectively ;the expression levels of each gene in SGT group were (1.62 ± 0.11 ) , (0.89 ± 0.03 ) ,(1.35 ± 0.06 ) and (0.87 ± 0.11 ) ,respectively . There was a statistically significant difference between groups (P<0.05) .Semi-quantitative Western blot results showed that the expression levels of ATG3 ,ATG12 ,p62 and Beclin1 protein in the liver of SGT group increased ,and the expression of LC3 B increased . Conclusion Sitagliptin potentially reduce hepatic fibrosis in T 2DM rats via promoting autophagy .%目的 研究磷酸西格列汀对T2DM大鼠肝细胞自噬的影响.方法 采用高脂、高糖饮食配合45 mg/kg STZ饲喂法建立T2DM大鼠模型.建模成功后将大鼠随机分组,分别用10 m/kg西格列汀灌胃(SGT组)、PBS灌胃(T2DM组)及10 IU/(kg·d)胰岛素腹腔注射(ISL组).PBS灌胃的正常大鼠作为正常对照组(NC).12周后测定血糖水平.HE、Masson染色评估肝纤维化程度;TUNEL法检测肝细胞损伤状况;采用RT-PCR测定ATG3、ATG12、p62与Beclin1 mRNA的表达;采用半定量Western blot测定ATG3、ATG12、p62,Beclin1和LC3B的蛋白水平.结果 西格列汀治疗12周后,与T2DM组比较,SGT组血糖降低(P<0.05).HE、Masson染色结果表明,SGT组肝纤维化程度改善.与NC组比较,T2DM组肝组织中自噬相关基因变化差异无统计学意义;T2DM组中ATG3、ATG12、p62、Beclin1的mRNA的表达量分别为(0.82±0.12)、(0.66±0.03)、(0.12±0.01)和(0.52±0.02);SGT组中各基因表达量分别为(1.62±0.11)、(0.89±0.03)、(1.35±0.06)和(0.87±0.11),组间比较,差异有统计学意义(P<0.05).半定量Western blot结果显示,SGT组肝组织中ATG3、ATG12、p62、Beclin1和LC3 B蛋白的表达水平均增加.结论 磷酸西格列汀可能通过促进肝组织自噬水平来减轻T2DM大鼠肝纤维化程度.
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