Fig. 9
From: Drp1 is widely, yet heterogeneously, distributed in the mouse central nervous system
Drp1 distribution under TEM. a. Considering that the fluorescent particles might overlap in vertical space, the distribution of mitochondrial Drp1 in the PAG brain was further observed at the subcellular level under an electron microscope. b. The distribution of Drp1 under TEM. The black particulate matter is colloidal gold particles, which represent Drp1-positive expression (red arrows). Brown represents the axon (A), blue represents the axon terminal (AT), red represents dendrites (D), and green represents the soma (S). Bar =500 nm. c. Quantity of Drp1 in the axon, axon terminal, dendrites and soma. The Kruskal-Wallis test results showed that the quantity of Drp1 was significantly different in four regions (p < 0.001). The quantity of Drp1 was higher in dendrites than axons (p < 0.001) and axon terminals (p < 0.001). The quantity of Drp1 was higher in soma than axons (p < 0.001) and axon terminals (p < 0.001). d. The ratio of Drp1 expression per unit area. Kruskal Wallis test results showed that ratio of Drp1 expression per unit area was significantly different in four regions (p < 0.001). The ratio was larger in dendrites than axons (p < 0.001) and axon terminals (p < 0.001). e. Quantity of mitochondria in the axon, axon terminal, dendrites and soma. Using an independent-sample Kruskal-Wallis test for analysis, the results showed that the quantity of mitochondria was significantly different in four regions (p < 0.001). Pairwise comparisons indicated that the quantity of mitochondria was greater in dendrites than axons (p < 0.001) and axon terminals (p = 0.001). The quantity of mitochondria was greater in soma than axons (p < 0.001) and axon terminals (p < 0.001). f. Proportion of Drp1 in mitochondria/total Drp1 in every region and mitochondria with Drp1/total mitochondria in every region. The proportion of Drp1 in mitochondria/total Drp1 in every region was quantified. The results showed that in dendrites, 4.72% of the Drp1 was localized to mitochondria (maximum), while in axons this proportion was only 2.5% (minimum). Similarly, the proportion of mitochondria with Drp1/total mitochondria in every region was also calculated. The results showed that in dendrites, 30.34% of the mitochondria localized with Drp1 (maximum), and this was proportion only 14.82% in axonal terminals (minimum). * p < 0.05, ** p < 0.01. Abbreviations: TEM: transmission electron microscope; PAG: periaqueductal gray