Background: 15d-$PGJ_2$ has been known to act as an anti-inflammatory agent and has anti-hypertensive effects. As a result of these properties, we examined the effect of 15d-$PGJ_2$ on the LPS-induced IL-8/CXCL8 mRNA expression in VSMCs from SHR. Methods: Effect and action mechanism of 15d-$PGJ_2$ on the expression of LPS-induced IL-8/CXCL8 mRNA in VSMCs from SHR and WKY were examined by using real-time polymerase chain reaction, electrophoretic mobility shift assay for NF-${kappa}B$ avtivity, Western blotting analysis for ERK and p38 phosphorylation and flow cytometry for NAD(P)H oxidase activity. Results: 15d-$PGJ_2$ decreased the expression of LPS-induced IL-8/CXCL8 mRNA in WKY VSMCs, but increased the expression of LPS-induced IL-8/CXCL8 mRNA in SHR VSMCs. The upregulatory effect of 15d-$PGJ_2$ in SHR VSMCs was mediated through PPAR${gamma}$, and dependent on NF-${kappa}B$ activation and ERK phosphorylation. However, inhibition of the p38 signaling pathway augmented the upregulatory effect of 15d-$PGJ_2$ on LPS-induced IL-8/CXCL8 mRNA. A NAD(P)H oxidase inhibitor inhibited the upregulatory effect of 15d-$PGJ_2$ on LPS-induced IL-8/CXCL8 mRNA expression in SHR VSMCs, and an increase in NAD(P)H oxidase activity was detected in SHR VSMCs treated with 15d-$PGJ_2$/LPS. Conclusion: Our results indicate that the upregulatory effect of 15d-$PGJ_2$ on LPS-induced IL-8/CXCL8 expression in SHR VSMCs is mediated through the PPAR${gamma}$ and ERK pathway, and may be related to NAD(P)H oxidase activity. However, p38 inactivation may also play an important role in 15d-$PGJ_2$/LPS-induced IL-8/CXCL8 expression in SHR VSMCs.