In the present study,we utilized db/db mice to investigate the mechanisms of apoptosis in brain and retinal neurons.A total of 30 male db/db mice aged 8–9 weeks were randomly assigned to the model group,Dihuangyinzi ...In the present study,we utilized db/db mice to investigate the mechanisms of apoptosis in brain and retinal neurons.A total of 30 male db/db mice aged 8–9 weeks were randomly assigned to the model group,Dihuangyinzi decoction(DHYZ)group(30.03 g/kg),and metformin(MET)group(0.58 g/kg),with 10 mice in each group.The control group comprised 10 db/m mice of the same background and age.Paired-associate learning(PAL)tests were conducted to evaluate the learning and memory functions of the mice.Histological assessments,including Hematoxylin-Eosin(H&E)and Nissl staining,were employed to observe changes in nerve cells in the hippocampus and retina.Immunohistochemistry and real-time fluorescence quantitative PCR were employed to detect the positive expression of anti-apoptotic factor Bcl-2 and pro-apoptotic factor Bax at the protein and mRNA levels in the hippocampus and retina.Western blotting analysis was adopted to assess protein expression levels of JNK,p-JNK,p38 MAPK,and p-p38 MAPK.Results revealed a significant decline in the correct rate of PAL test results in the model group(P<0.001),accompanied by increased reaction and delay times(P<0.001)and higher blood glucose levels(P<0.001).H&E and Nissl staining indicated a reduction in the number of nerve cells in the CA1 area of the hippocampus in the model group,with scattered arrangement and decreased Nissl corpuscles.Positive expression and mRNA expression of Bax in the hippocampus and retina increased significantly(P<0.001),while positive expression and mRNA expression of Bcl-2 decreased(P<0.001).Protein expression levels of p-JNK/JNK and p-p38 MAPK/p38 MAPK showed a significant increase(P<0.001).The DHYZ and MET groups exhibited enhanced accuracy in PAL experiments(P<0.05),decreased reaction time and delay time(P<0.05),and reduced blood glucose levels(P<0.05).The number of neurons in the CA1 region of the hippocampus increased,morphological structure improved,and the arrangement of the hippocampal structure became more orderly.Additionally,no obvious vacuolization was observed in the neuronal cell layer.The number of Nissl bodies increased,and the layers of the retina were closely arranged,with an increase in the number of Nissl bodies.Positive expressions of Bax in the hippocampus and retina,both at the protein and mRNA levels,decreased significantly(P<0.001),while positive expressions of Bcl-2 and its mRNA increased(P<0.01,P<0.001).Furthermore,the protein expressions of p-JNK/JNK and p-p38 MAPK/p38 MAPK decreased significantly(P<0.01).This study suggested that DHYZ decoction could inhibit the JNK/p38 MAPK signaling pathway,thereby increasing the anti-apoptotic factor Bcl-2 and reducing the expression of the pro-apoptotic factor Bax,consequently inhibiting apoptosis in the hippocampal CA1 region and retinal neurons of db/db mice.展开更多
文摘In the present study,we utilized db/db mice to investigate the mechanisms of apoptosis in brain and retinal neurons.A total of 30 male db/db mice aged 8–9 weeks were randomly assigned to the model group,Dihuangyinzi decoction(DHYZ)group(30.03 g/kg),and metformin(MET)group(0.58 g/kg),with 10 mice in each group.The control group comprised 10 db/m mice of the same background and age.Paired-associate learning(PAL)tests were conducted to evaluate the learning and memory functions of the mice.Histological assessments,including Hematoxylin-Eosin(H&E)and Nissl staining,were employed to observe changes in nerve cells in the hippocampus and retina.Immunohistochemistry and real-time fluorescence quantitative PCR were employed to detect the positive expression of anti-apoptotic factor Bcl-2 and pro-apoptotic factor Bax at the protein and mRNA levels in the hippocampus and retina.Western blotting analysis was adopted to assess protein expression levels of JNK,p-JNK,p38 MAPK,and p-p38 MAPK.Results revealed a significant decline in the correct rate of PAL test results in the model group(P<0.001),accompanied by increased reaction and delay times(P<0.001)and higher blood glucose levels(P<0.001).H&E and Nissl staining indicated a reduction in the number of nerve cells in the CA1 area of the hippocampus in the model group,with scattered arrangement and decreased Nissl corpuscles.Positive expression and mRNA expression of Bax in the hippocampus and retina increased significantly(P<0.001),while positive expression and mRNA expression of Bcl-2 decreased(P<0.001).Protein expression levels of p-JNK/JNK and p-p38 MAPK/p38 MAPK showed a significant increase(P<0.001).The DHYZ and MET groups exhibited enhanced accuracy in PAL experiments(P<0.05),decreased reaction time and delay time(P<0.05),and reduced blood glucose levels(P<0.05).The number of neurons in the CA1 region of the hippocampus increased,morphological structure improved,and the arrangement of the hippocampal structure became more orderly.Additionally,no obvious vacuolization was observed in the neuronal cell layer.The number of Nissl bodies increased,and the layers of the retina were closely arranged,with an increase in the number of Nissl bodies.Positive expressions of Bax in the hippocampus and retina,both at the protein and mRNA levels,decreased significantly(P<0.001),while positive expressions of Bcl-2 and its mRNA increased(P<0.01,P<0.001).Furthermore,the protein expressions of p-JNK/JNK and p-p38 MAPK/p38 MAPK decreased significantly(P<0.01).This study suggested that DHYZ decoction could inhibit the JNK/p38 MAPK signaling pathway,thereby increasing the anti-apoptotic factor Bcl-2 and reducing the expression of the pro-apoptotic factor Bax,consequently inhibiting apoptosis in the hippocampal CA1 region and retinal neurons of db/db mice.
