Mast cell density: a quantitative index of acute liver inflammation.
OBJECTIVE
To evaluate mast cell (MC) density, in liver tissues taken from young and aging rats treated with carbon tetrachloride (CCl4) or untreated, as a quantitative marker of acute liver inflammation and to investigate whether the density of MCs varied with the rats' age.


METHODS
Rats aged 2, 6, 12 and 19 months treated intraperitoneally with CCl4 were killed 2 and 24 hours after intoxication. Hepatocellular damage was established by measuring alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity. Four histologic sections of 12 specimens from each age group were stained with toluidine blue to identify the MCs, which were counted using a computer-assisted image analysis system.


RESULTS
Histology showed hepatocellular necrosis with inflammatory infiltration both 2 and 24 hours after intoxication. Serum AST levels were high in the 6- and 12-month-old rats, whereas ALT levels were high in the those aged 2 and 19 months. Two and 24 hours after intoxication, MC density increased considerably in young rats but less so in rats aged 19 months.


CONCLUSIONS
MC density can be a useful marker of acute liver inflammation. The greater density in young rats suggests that older rats have a reduced immune response or recruit fewer MCs.
Grizzi
Fabio
F
Scientific Direction, Istituto Clinico Humanitas, Rozzano MI, Italy. fabio.grizzi@humanitas.it
Franceschini
Barbara
B
Barbieri
Barbara
B
Gagliano
Nicoletta
N
Arosio
Beatrice
B
Chiriva-Internati
Maurizio
M
Annoni
Giorgio
G
Dioguardi
Nicola
N
D000367:Age Factors; D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D002251:Carbon Tetrachloride / Q000008:administration & dosage / Q000633:toxicity*; D002452:Cell Count; D056486:Chemical and Drug Induced Liver Injury / Q000097:blood / Q000473:pathology*; D007091:Image Processing, Computer-Assisted; D007274:Injections, Intraperitoneal; D008297:Male; D008407:Mast Cells / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D002251:Carbon Tetrachloride; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase