Abnormal lipid accumulation in sebaceous glands (SGs) and modified sebaceous glands. Representative images of skin and eyelid stained with Oil Red O (ORO) for lipids, showing lipid accumulation in mitochondrial DNA (mtDNA) depleter mice after 8 months of doxycycline induction. A: Skin sebaceous glands (yellow asterisks). B: Quantification of ORO integrated density in SG compared with control littermate. C: Modified eyelid sebaceous glands (meibomian glands; yellow asterisks). D: Quantification of ORO integrated density in meibomian glands compared with control littermate. E: Oil Red O stain, showing no or minimal lipid layer on skin surface compared with continuous lipid layer in control skin (black dashed line). F: Quantification of ORO integrated density on the skin surface. G: Representative gross image, showing distension of meibomian glands in mtDNA depleter mice after 2 months of doxycycline induction compared with control. H: Quantitative RT-PCR analysis of lipogenesis-regulating genes (Scd1, Prdm1, Plin2, Ppara, Pparg, and Ppard) and androgen receptor gene (Ar) in mRNA extracted from the preputial gland of male mice after 8 months of doxycycline induction, showing higher expression in mtDNA depleter samples compared with control. Transcripts were done in triplicates and were determined by normalizing to β-actin. Data are given as means ± SD (B, D, F, and H). ∗P ≤ 0.05, ∗∗∗P ≤ 0.001, and ∗∗∗∗P ≤ 0.0001 (t-test). Scale bars = 20 μm (A, C, and E).