Table 2.
Transmission Electron Microscopy Measurements and Stereological Analysis of Media, Medial Smooth Muscle Cells, and Other Components of Ovine Middle Cerebral Artery with Development
| Parameter | Fetus | Adult | |
|---|---|---|---|
| 95 GD | 140 GD | ||
| Lumen | |||
| Diameter (μm) | 623 ± 80a, e (46) | 941 ± 73b (70) | 1351 ± 68 |
| Vessel Wall | |||
| Media thickness (μm) | 13.7 ± 2.3a, f (47) | 21.3 ± 0.9c (73) | 29.2 ± 2.3 |
| Media cross-section area (μm2 · 103) | 26.0 ± 3.2a, d (20) | 67.1 ± 6.8b (52) | 128.7 ± 12.0 |
| Number of SMC cell layers in media | 3.3 ± 0.5b, d (45) | 5.6 ± 0.2 (76) | 7.4 ± 1.0 |
| SMC volume fraction in media | 0.72 ± 0.01 (111) | 0.69 ± 0.01 (106) | 0.65 ± 0.04 |
| SMC numerical density in media (μ−3 · 10−3) | 0.65 ± 0.20 (181) | 0.36 ± 0.02c | 0.36 ± 0.06 |
| SMC number per unit arterial length (N1), (μ−1) | 15.3 ± 2.9b, f (33) | 23.6 ± 1.5c (51) | 46.3 ± 7.6 |
| Smooth Muscle Cell | |||
| Length (lc), (μ) | 102 ± 16c, e (67) | 171 ± 14 (113) | 151 ± 15 |
| Cross-section area (ac), (μ2) | 13.8 ± 2.3 | 11.4 ± 0.4 (83) | 13.8 ± 2.3 |
| Volume (vc), (μ3) | 1407 ± 271 (69) | 1937 ± 105 (95) | 2042 ± 427 |
| Nucleus length (ln), (μ) | 15.2 ± 2.2c (63) | 20.3 ± 2.6 (84) | 24.2 ± 2.2 |
| Nucleus as % SMC (mid-length) cross section area | 42.6 ± 2.0a, f (203) | 36.6 ± 1.2a (174) | 21.0 ± 0.6 |
| Nuclear heterochromatin as % nuclear area | 31.3 ± 2.0 a, f (63) | 38.5 ± 2.2b (77) | 49.9 ± 0.3 |
| Dense body profiles as % SMC cross section area | 3.4 ± 0.7a, d (33) | 6.8 ± 0.6b (67) | 10.2 ± 0.4 |
| Basal lamina thickness (nm) | 75.3 ± 4.0b (51) | 69.2 ± 3.8b (47) | 148.0 ± 14.8 |
| Extracellular Matrix | |||
| Electron dense structures as % ECM cross section area | 44.7 ± 3.9a, e (48) | 61.8 ± 2.5b (81) | 75.4 ± 2.5 |
| Other Variables | |||
| Base soluble protein (% Dry Wt)º | 24.5 ± 2.2 (102) | 23.9 ± 2.7 | |
| Base soluble protein (μg protein · mg wet wt−1) | 23 ± 3+ (70) | 33±4 | |
| DNA Content (relative to tissue wet weight)º | 5.0 ± 0.3 (147) | 3.4 ± 0.3 | |
| α-Actin (% of adult value) | 105 ± 10 (105) | 100 | |
| α-Tubulin (% of adult value) | 240 ± 40b (240) | 100 | |
| Water (% Wet Wt)º | 80.0 ± 0.8 (105) | 76.5 ± 0.7 | |
Values are mean ± SE of 5 or more in each group;
+
Newborn; Values in parentheses represent % of adult value;
Significantly different from adult value:
a
P<0.001;
b
P<0.01;
c
P<0.05;
Significantly different from GD 140:
d
P<0.001;
e
P<0.01;
f
P<0.05 (From Goyal et al, 2012 [10]);
º
Elliott & Pearce, 1995 [147]