Impact of proteasome inhibitor MG-132 on expression of NF-κB, IL-1β and histological remodeling after myocardial infarction.

The aim of the present study was to investigate the impact of carbobenzoxy-Leu-Leu-leucinal (MG-132) on myocardial remodeling in rats with myocardial infarction (MI) and investigate the possible underlying mechanisms. The rat model of MI was established, followed by administration of MG-132 (MG group), pyrrolidine dithiocarbamic acid (PDTC group) or normal saline (MI group) for 28 days. The expression of nuclear factor-κB (NF-κB) p65, interleukin 1β (IL-1β) and matrix metalloproteinase 2 (MMP-2), as well as the total volume of collagen and the ratio of type I/III collagen were then detected. Total collagen, including type I and III collagen, and the ratio of type I/III collagen were significantly increased in MI rats compared with those in the sham group (P<0.01), while it was significantly decreased in the PDTC and MG groups compared with that in the MI group (P<0.01). A similar trend was identified for the expression of NF-κB, IL-1β and MMP-2, which was significantly increased in the MI group compared with that in the sham group (P<0.01), while it was significantly decreased in the MG and PDTC groups compared with that in the MI group (P<0.01). In conclusion, MG-132 was demonstrated to improve post-MI tissue remodeling, and the mechanism may be associated with the inhibition of NF-κB activation and the downregulation of inflammatory cytokines, such as IL-1β.