Betaine Treatment Attenuates Chronic Ethanol-Induced Hepatic Steatosis and Alterations to the Mitochondrial Respiratory Chain Proteome

Figure 7

Betaine prevents the chronic ethanol-mediated loss in oxidative phosphorylation proteins. Representative (a) one- and (c) two-dimension blue native (BN)-PAGE proteomic gels of mitochondria isolated from rats fed control, ethanol, control + betaine, or ethanol + betaine diets as detailed in Section 2. (a) For these gels, 250 μg of mitochondrial protein were subjected to 1D BN-PAGE. (c) The 1D gel strips were overlaid across a Tris-Tricine-SDS-PAGE gel to resolve the individual polypeptides that comprise each oxidative phosphorylation system complex. The proteins that comprise each complex (I, V, III, IV, and II) appear as vertically aligned spots on the 2D gel. (b) Comparison of the relative quantities of complexes I, V, III, and IV in liver mitochondria from the control; control + betaine; ethanol, and ethanol + betaine. Statistical analyses for data presented in panel B: 2-factor ANOVA on raw densitometry values—complex I: ethanol 𝑃=0.0002, betaine 𝑃=0.92, interaction 𝑃=0.02; complex V: ethanol 𝑃=0.016, betaine 𝑃=0.72, interaction 𝑃=0.23; complex III: ethanol 𝑃=0.005, betaine 𝑃=0.92, interaction 𝑃=0.31; complex IV: ethanol 𝑃=0.15, betaine 𝑃=0.62, interaction 𝑃=0.045; complex II: ethanol 𝑃=0.54, betaine 𝑃=0.98, interaction 𝑃=0.80. (d) Complex IV, subunit 1 protein levels were measured by immunoblotting. The bar graph results represent the mean volume integration units (V.I.U) ± S.E.M. for 𝑛=8 animals per group. Values not sharing a common letter are statistically different, 𝑃<0.05. The top figure shows representative immunoblots of subunit 1 protein for control, ethanol, and betaine supplemented control and ethanol-fed rats.

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