A Simple Method to Estimate the Number of Autophagic Elements by Electron Microscopic Morphometry in Real Cellular Dimensions

Table 1

Approximate diameter (𝐷_𝑐), average volume (𝑉_𝑐), and number of autophagic elements (𝑁_𝑐) in a cell with 5000 μm³ cytoplasm, calculated from the specific surface values (𝑆_𝑣 /𝑉_𝑣 = 𝑆_𝑠𝑝) from real experimental samples of liver and exocrine pancreatic cells. The details of calculation are described in the text.

Experimental system and treatment	Category	𝑆𝑣; μm^2/μm^3	𝑉𝑣; μm^3/μm^3	𝑆𝑠𝑝; μm^2/μm^3	𝐷𝑐; μm	𝑉𝑐; μm^3	𝑁𝑐 in; 5000 μm^3
Isolated hepatocytes
Plus amino acid mixture 30 min	Afs	0,0023	0,0003	7,6	0,79	0,26	6
	Al	0,0147	0,0022	6,8	0,88	0,36	30
Plus amino acid mixture 3 h	Afs	0,0047	0,0006	7,4	0,81	0,28	11
	Al	0,0367	0,0072	5,1	1,18	0,85	42
Minus amino acid mixture; 3 h 30 min	Afs	0,0472	0,0067	7,0	0,86	0,33	102
	Al	0,1333	0,0215	5,9	0,97	0,47	195
Propylamine 10 mM 3 h	Afs	0,0856	0,0124	6,9	0,87	0,34	180
	Al	0,0563	0,0084	6,7	0,90	0,38	112
	Alam	0,2925	0,1170	2,5	2,40	7,24	81
Hepatocytes in vivo
3 h feeding	Afs	0,0024	0,0003	7,9	0,76	0,23	7
	Al	0,0040	0,0005	7,9	0,76	0,23	11
	Db	0,0088	0,0008	11,0	0,55	0,08	47
24 h fasting	Afs	0,0101	0,0014	7,2	0,84	0,31	23
	Al	0,0171	0,0022	7,8	0,77	0,24	46
	Db	0,0079	0,0008	9,9	0,61	0,12	34
Ad libitum feeding	Afs	0,0025	0,0003	8,5	0,71	0,18	8
	Al	0,0048	0,0006	8,0	0,75	0,22	14
Vinblastine treatment; 0,1 mg/g 2 h	Afs	0,0778	0,0105	7,4	0,81	0,28	189
	Al	0,0648	0,0086	7,5	0,80	0,26	163
Leupeptin treatment; 0,12 mg/g 2 h	Afs	0,0450	0,0054	8,3	0,72	0,20	138
	Al	0,1095	0,0278	3,9	1,52	1,85	75
Exocrine pancreas cells in vivo
24 h fasting	Afs	0,0050	0,0007	7,2	0,83	0,30	12
	Al	0,0061	0,0009	6,8	0,89	0,36	12
Ad libitum feeding	Afs	0,0016	0,0002	7,9	0,76	0,23	4
	Al	0,0024	0,0003	7,8	0,77	0,23	6
Vinblastine treatment; 0,1 mg/g 1 h	Afs	0,0447	0,0063	7,1	0,85	0,32	99
	Al	0,0233	0,0034	6,8	0,88	0,35	48
Vinblastine treatment; 0,1 mg/g 1,5 h	Afs	0,1073	0,0159	6,8	0,89	0,37	216
	Al	0,0401	0,0060	6,7	0,90	0,38	79
Vinblastine treatment; 0,1 mg/g 6 h	Afs	0,3362	0,0518	6,5	0,92	0,41	626
	Al	0,3081	0,0517	6,0	1,01	0,53	484

Afs: autophagosome (early autophagic vacuole), Al: autolysosome (late autophagic vacuole), Db: dense body, Alam: swollen electron-lucent amine type of autolysosome.
The experimental animals were from male mice for in vivo treatments and from rats for isolated cells. The evaluated cytoplasmic area was in the range of 9–16000 μm². For further details of electron microscopy, morphometry, and experimental systems see, for example, in [5–10].