M. Aoyagi et al., EXPRESSION OF P53 PROTEIN AND P53 GENE TRANSCRIPTS IN RABBIT CAROTID ARTERIES AFTER BALLOON DENUDATION, HISTOCHEM C, 107(5), 1997, pp. 365-370
Smooth muscle cell (SMC) proliferation may be positively or negatively
regulated by various factors after arterial wall injury. We investiga
ted the hypothesis that the p53 protein may play a role in regulating
SMC proliferation. We examined p53 protein expression and p53 gene tra
nscript distribution in rabbit carotid arteries over a period of 6 wee
ks after balloon denudation in relation to SMC proliferation. The numb
er of p53-positive SMCs in the neointima reached a maximum 2 weeks aft
er balloon denudation when proliferating SMCs decreased and were confi
ned to the luminal surface of the intima. The p53-positive SMCs in the
neointima almost paralleled the distribution of proliferating cell nu
clear antigen (PCNA)-positive SMCs but not that of Ki-67-positive cell
s. Double immunofluorescence showed the simultaneous nuclear localizat
ion of both p53 protein and PCNA in intimal SMCs. Strong signals for p
53 gene transcripts, identified by in situ hybridization, were observe
d in SMCs showing positive immunostaining for p53 protein. Our results
indicate that p53 protein and p53 gene transcript levels increase, ar
e closely Linked to the proliferation of SMCs in the thickened intima,
and play a key role in the regulation of cell proliferation during th
e repair process after arterial wall injury.