Anti-inflammatory Effect And Mechanism Of Ceftiofur

Ceftiofur is a new broad-spectrum, third-generation cephalosporin antibiotic for veterinary use. Ceftiofur inhibits bacterial cell wall synthesis by interfering with enzymes essential for peptidoglycan synthesis, which results in lysis of the bacterial cell and accounts for the bactericidal nature of this antibiotic. Consequently, ceftiofur should be effective against a wide range of contagious mastitis pathogens. It has been widely used to treat a broad array of infectious diseases caused by Gram-positive and Gram-negative bacteria, such as pneumonia, peritonitis, and mastitis in dairy cattle. Among third-generation cephalosporins, cefodizime was shown to modulate the release of inflammatory cytokines. Importantly, ceftiofur has a similar structural formula to cefodizime, though ceftiofur's effect on septic shock has not yet been reported. Therefore, we investigated whether ceftiofur has any anti-inflammatory effects.In this paper, we investigated in vitro[LPS-induced murine RAW264.7 macrophages], the effect of ceftiofur on the generation of cytokines involved in the inflammatory process, such as TNF-α, IL-1β, IL-6, and IL-10. We found that ceftiofur can downregulate tumor necrosis factor-α(TNF-α), interleukin-1β(IL-1β), and interleukin-6 (IL-6), but did not affect interleukin-10 (IL-10) production.Recently, the signaling pathways participating in LPS-induced macrophage activation have been extensively characterized. NF-κB and MAPKs are the most classical pathway. NF-κB is one of the most ubiquitous transcription factors and regulates the genes involved in cellular proliferation, inflammatory responses, and cell adhesion. MAPKs are a family that includes ERK, p38 and JNK. ERK are activated by a variety of cell growth and differentiation stimuli and play a central role in mitogenic signaling. The p38 and JNK cascades are primarily activated by various environmental stresses and by the proinflammatory cytokines TNF-αand IL-1β. NF-κB and MAPKs are therefore known to be important targets for anti-inflammatory molecules. We further investigated signal transduction mechanisms to determine how ceftiofur affects in vitro[LPS-induced murine RAW264.7 macrophages]. Our results suggested that ceftiofur suppresses LPS-induced proinflammatory cytokine production by inhibiting the activation of both MAPKs and the transcription factor NF-κB in RAW264.7 cells.We have previously shown that ceftiofur can inhibit LPS-stimulated TNF-α, IL-1βand IL-6 secretion in RAW264.7 cells via activation of the NF-κB and MAP-kinase pathways in vitro. Although these observations strongly suggest that ceftiofur could influence host defences, the effect of this drug on these responses in patients and on disease associated with these responses has not been demonstrated. This effect was studied using a murine model that measured mortality and early cytokine responses after challenge with endotoxin. The results presented here clearly demonstrated that ceftiofur can prevent mortality associated with endotoxin challenge and significantly decreased plasma levels of TNF-α, IL-1β, and IL-6, but increased plasma levels of IL-10. We concluded that the effect of ceftiofur on IL-10 production was different between in vitro and in vivo analyses. In addition to the difference in the treatment protocol, differences in conditions between in vivo and in vitro experiments may be responsible for this discrepancy.Our results suggested that ceftiofur suppresseed LPS-induced proinflamm- atory cytokine production by inhibiting the activation of both MAPKs and the transcription factor NF-κB in RAW264.7 cells; ceftiofur had a beneficial effect on LPS-induced endotoxemia caused by LPS through its modulation of cytokine levels in vivo. Future studies should focus on the basic mechanisms governing ceftiofur inhibition of pro-inflammatory cytokine production. In addition, future studies should also address the on clinical relevance of our studies. It is not clear at present how ceftiofur inhibits the NF-κB and MAPKs signaling in stimulated cells, and events upstream of the TLR level should be investigated.