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Tables

Table S1. Primers used for real-time PCR
Table S2. Antibodies used in the Western Blot assay

Figure legends

Figure 1. Effect of puerarin on general indicators of STZ-induced type 1 diabetic rats. Rats were treated with 100 mg kg-1 day-1puerarin intragastrically for two months. (a) Change in body weight was detected every week. (b) Food intake at the 8th week. (c) Fasting blood glucose at the 8th week. (d) Blood-glucose curve of IPGTT. (e) AUC of IPGTT. (f) LA content in serum. (g) PA content in serum. a, d, e, Data are represented as the means ± SEM (control, n = 6; model, n = 10; puerarin, n = 8). Statistical analysis tested by one-way ANOVA with Dunnett’s multiple comparisons test analysis. b, f, g, Data are represented as the means ± SEM (n = 5). Statistical analysis tested by one-way ANOVA with Dunnett’s multiple comparisons test analysis. c, Data are represented as the means ± SEM (control, n = 6; model, n = 10; puerarin, n = 10). Statistical analysis tested by one-way ANOVA with Dunnett’s multiple comparisons test analysis. # p < 0.05, ## p < 0.01 and ### p < 0.001 vs. the control group. * p < 0.05 vs. the model group.
Figure 2. Puerarin increased skeletal muscle strength and weight in type 1 diabetic rats. a-c, Effect of 100 mg kg-1 day-1 puerarin on muscle strength. (a) Foreleg tensile force. (b) Time on inclined plane. (c) Time on hanging wire. d-i, Muscle weights and muscle tissue indexes (muscle weight/body weight). (d) Soleus weight. (e) Soleus tissue index. (f) TA weight. (g) TA tissue index. (h) Gastrocnemius weight. (i) Gastrocnemius tissue index. Data presented are individual values with means ± SEM from n=5 rats for each group. Statistical analysis tested by one-way ANOVA with Dunnett’s multiple comparisons test analysis. # p < 0.05, ## p < 0.01 and ### p < 0.001 vs. the control group. * p < 0.05, ** p < 0.01, *** p < 0.001 and vs. the model group.
Figure 3.Puerarin improved skeletal muscle fiber area in type 1 diabetic rats. (a) Representative images of H&E staining of soleus, TA and gastrocnemius muscle (400 x magnification). (b) Cross-sectional area of soleus muscle. (c) Cross-sectional area of TA muscle. (d) Cross-sectional area of gastrocnemius muscle. e-g, Frequency distribution of cross-sectional area of three types of muscle fibers in the (e) soleus, (f) TA, and (g) gastrocnemius muscles. b-d, Values shown are the means ± SEM from 3 fields, n=5. Statistical analysis tested by one-way ANOVA with Dunnett’s multiple comparisons test. e-g, Statistical analysis tested by Chi-square (and Fisher’s exact) test. ### p < 0.001 vs. the control group. *** p < 0.001 and vs. the model group.
Figure 4. Puerarin downregulated the expression of muscle atrophic markers in type 1 diabetic rats. a-c, Total mRNA extracted from the soleus, TA and gastrocnemius muscles was used for real-time PCR analysis. (a) Atrogin-1, Murf-1 and MyHC expression in the soleus muscle. (b) Atrogin-1, Murf-1 and MyHC expression in the TA muscle. (c) Atrogin-1, Murf-1, MyHC and Mstn expression in the gastrocnemius muscle. d-g, Total protein extracted from the gastrocnemius muscle was used for Western Blot analysis. (d-g) Immunoblot analysis of Atrogin-1, Murf-1 and MyHC of the gastrocnemius muscle. Data are represented as the means ± SEM (n=5). Statistical analysis tested by one-way ANOVA with Dunnett’s multiple comparisons test analysis. # p < 0.05, ## p < 0.01 and ### p < 0.001 vs. the control group. * p < 0.05, ** p < 0.01, *** p < 0.001 and vs. the model group.
Figure 5.Effect of puerarin on muscle fiber phenotype in type 1 diabetic rats. Frozen sections of gastrocnemius muscle samples were subject to SDH and COX staining. (a) Representative images of SDH (above) and COX (below) staining in the gastrocnemius muscle. (b) Integrated optical density analysis of SDH staining. (c) Muscle fiber number ratio (type I/type II) in SDH staining. (d) Integrate optical density analysis of COX staining. (e) Muscle fiber number ratio (type I/type II) in COX staining. (f) Analysis of muscle fiber area of type I, type IIA and type IIB in SDH staining. (g) Analysis of muscle fiber area of type I, type IIA and type IIB in COX staining. (h) Myh1, Myh2, Myh4 and Myh7 expression in the gastrocnemius muscle. b-e, Values shown are means ± SEM from n=5. Statistical analysis tested by one-way ANOVA with Dunnett’s multiple comparisons test analysis. f, g, Values shown are means ± SEM from 4 fields (n=6). h, Values shown are means ± SEM from n=5. Statistical analysis tested by one-way ANOVA with Dunnett’s multiple comparisons test analysis. # p < 0.05, ## p < 0.01 and ### p < 0.001 vs. the control group. * p < 0.05, ** p < 0.01, *** p < 0.001 and vs. the model group.
Figure 6.Puerarin decreased muscle atrophic markers in L6 myotubes. a-d, Fully differentiated L6 rat myotubes were treated with D-glucose. (a, b) Dose-response effect of high glucose (0, 50, 100 mM) for 48 h on the expression of muscle atrophic markers (a) Atrogin-1 and (b) Murf-1 gene. (c, d) Time-response effect of 100 mM glucose (0 h, 6 h, 12 h, 24 h, 48 h, 72 h) on (c) Atrogin-1 and (d) Murf-1 gene expression. e-h, 10, 100, 1000 μM puerarin or 100 nM insulin or 100 mM mannitol were used to treat fully differentiated L6 rat myotubes with or without 100 mM glucose for 48 h, and total mRNA was extracted for real-time PCR analysis. (e) Expression of Atrogin-1. (f) Expression of Murf-1. (g) Expression of Mstn. (h) Expression of MyHC. Data are represented as the means ± SEM from n=3 experiments. Statistical analysis tested by one-way ANOVA with Dunnett’s multiple comparisons test analysis. # p < 0.05, ## p < 0.01 and ### p < 0.001 vs. DM group. * p < 0.05, ** p < 0.01, *** p < 0.001 and vs. HG group.
Figure 7.Puerarin ameliorated muscle atrophy induced by high glucose in L6 myotubes. a-d, Fully differentiated L6 myotubes were treated with 10, 100, 1000 μM puerarin or 100 nM insulin with or without 100 mM glucose for 48 h, and total protein was extracted for Western Blot analysis. (a-d) Immunoblot analysis of Atrogin-1, Murf-1 and MyHC. e-g, Immunofluorescence staining for MyHC (100 x magnification) in L6 rat myotubes treated with 10, 100, 1000 μM puerarin or 100 nM insulin with or without 100 mM glucose for 48 h. (e) Representative images of immunofluorescence staining for MyHC. (f) Myotube average area analysis of L6 rat myotubes. (g) Frequency distribution of myotube area. b-d, Data are represented as the means ± SEM from n=3 experiments. Statistical analysis tested by one-way ANOVA with Dunnett’s multiple comparisons test analysis. f, Values shown are means ± SEM from 5 fields (n=3). Statistical analysis tested by one-way ANOVA with Dunnett’s multiple comparisons test analysis. g, Statistical analysis tested by Chi-square (and Fisher’s exact) test. ## p < 0.01 and ### p < 0.001 vs. DM group. * p < 0.05, ** p < 0.01, and *** p < 0.001 vs. the HG group.
Figure 8. Puerarin attenuated autophagy but upregulated Akt/mTOR signaling in L6 myotubes. Fully differentiated L6 myotubes were treated with 10, 100, or 1000 μM puerarin or 100 nM insulin with or without 100 mM glucose for 48 h, and total protein was extracted for Western Blot analysis. (a-d) Immunoblot analysis of phosphorylation of ULK1, p62 and LC3II/I. (e-j) Immunoblot analysis of phosphorylation of Akt, FoxO3a, mTOR, p70S6K and 4EBP1. Data are represented as the means ± SEM from n=3 experiments. Statistical analysis tested by one-way ANOVA with Dunnett’s multiple comparisons test analysis. # p < 0.05, ## p < 0.01 and ### p < 0.001 vs. DM group. * p < 0.05, ** p < 0.01, *** p < 0.001 and vs. HG group.