title: Histochemical characteristics of soleus muscle in angiotensin-converting enzyme gene knockout mice.
abstract: 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.
authors.affiliation: Department of Cardiology, School of Medicine, Faculty of Science, Fukuoka University, Fukuoka, Japan.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.forename: Naoko
authors.initials: N
authors.lastname: Shono
authors.forename: Ping
authors.initials: P
authors.lastname: Fan
authors.forename: Setsuko
authors.initials: S
authors.lastname: Ando
authors.forename: Huali
authors.initials: H
authors.lastname: Xu
authors.forename: Shiro
authors.initials: S
authors.lastname: Jimi
authors.forename: Shin-ichiro
authors.initials: S
authors.lastname: Miura
authors.forename: Koichiro
authors.initials: K
authors.lastname: Kumagai
authors.forename: Khin Mimi
authors.initials: KM
authors.lastname: Win
authors.forename: Akira
authors.initials: A
authors.lastname: Matsunaga
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Iwasaski
authors.forename: Keijiro
authors.initials: K
authors.lastname: Saku
mesh_terms: 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*
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D007703:Peptidyl-Dipeptidase A