Histochemical characteristics of soleus muscle in angiotensin-converting enzyme gene knockout mice.
We examined the histochemical characteristics of soleus muscle in the angiotensin-converting enzyme (ACE) gene (Ace in mice, ACE in humans) knockout mice. Serial sections of soleus muscle of wild-type (Ace+/+, n=20) and heterozygous mutant (Ace+/-, n=24) mice were stained for myosin adenosine triphosphatase activity to identify different muscle fiber types. Capillaries were visualized by amylase-periodic acid-Schiff staining. ACE activity in the serum and gastrocnemius muscle was higher in male mice than in female mice. Female and male Ace+/- mice had markedly lower ACE activity in the serum and the gastrocnemius muscle than did female and male Ace+/+ mice, respectively. In both male and female mice, the composition of fiber types (type I and IIa) did not differ significantly between Ace+/+ and Ace+/- mice. There was no significant gender difference in capillary density. Ace+/- mice had significantly more capillaries around type IIa fibers (5.44 +/- 0.18 vs. 5.01 +/- 0.13, p<0.05) than Ace+/+ mice. The differences in the number of capillaries around type I fibers and in the number of capillaries around per fiber (capillary:fiber ratio) between Ace+/- and Ace+/+ mice were not significant (p<0.1). There was no significant difference in the mean cross-sectional area occupied by one capillary and the number of capillaries per fiber area between Ace+/+ and Ace+/- mice. In conclusion, knockout of the Ace gene in mice increased capillary density, as expressed by the mean number of capillaries around type IIa fibers. This finding suggests a possible mechanism for the cardioprotective effects of ACE inhibitors.
Zhang
Bo
B
Department of Cardiology, School of Medicine, Faculty of Science, Fukuoka University, Fukuoka, Japan.
Shono
Naoko
N
Fan
Ping
P
Ando
Setsuko
S
Xu
Huali
H
Jimi
Shiro
S
Miura
Shin-ichiro
S
Kumagai
Koichiro
K
Win
Khin Mimi
KM
Matsunaga
Akira
A
Iwasaski
Hiroshi
H
Saku
Keijiro
K
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000818:Animals; D002196:Capillaries / Q000166:cytology; D002320:Cardiovascular Physiological Phenomena / Q000187:drug effects; D002319:Cardiovascular System / Q000187:drug effects; D005260:Female; D015870:Gene Expression; D006579:Heterozygote; D006651:Histocytochemistry; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D018656:Muscle Fibers, Fast-Twitch / Q000166:cytology / Q000201:enzymology; D018657:Muscle Fibers, Slow-Twitch / Q000166:cytology / Q000201:enzymology; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000166:cytology* / Q000201:enzymology; D009154:Mutation; D007703:Peptidyl-Dipeptidase A / Q000032:analysis* / Q000097:blood / Q000235:genetics*
D000806:Angiotensin-Converting Enzyme Inhibitors; D007703:Peptidyl-Dipeptidase A