Figure 4: Transmission electron microscopy image. (a) Representative electron micrographs of CON rats mesenteric arteries with normal cell morphology including integrity endothelial cells, normal nucleus and mitochondria (×3.0k); (b) Disintegrating endothelial cell layer in MS rats mesenteric arteries (indicated by yellow star, ×7.0k); (c) Abnormal cell morphology including the expanding endoplasmic reticulum, fractured mitochondrial crest and the fusion of crest and membrane, were detectable in MS rats mesenteric arteries, so there were blurred structure (×7.0k); (d) Representative electron micrographs of MS + CIHH rats mesenteric arteries with integrity endothelial and normal mitochondria structures (×3.0k); (e) Image of CON rats mesenteric arteries incubated with CQ (×8.0k); (f) Image of CIHH rats mesenteric arteries incubated with CQ (×8.0k); (g) Image of MS rats mesenteric arteries incubated with CQ (×8.0k); (h) Image of MS + CIHH rats mesenteric arteries incubated with CQ (×8.0k). A partially enlarged image of mitochondria and endoplasmic reticulum was placed in the upper left corner (mitochondria were indicated by yellow arrows, endoplasmic reticulum by green arrows and tight junction by circle). Autophagosomes were indicated by red arrows. CIHH: Chronic intermittent hypobaric hypoxia; AMPK: Adenosine mono-phosphate-activated protein kinase; mTOR: Mammalian target of rapamycin; MS: Metabolic syndrome; CON: Control.