In Vitro Pro-inflammatory Regulatory role of Substance P in Alveolar Macrophages and Type II Pneumocytes after JP-8 Exposure.

The effects of JP-8 on pro-inflammatory cytokine interleukin (IL)-1alpha,beta and nitric oxide (NO) secretion as well as the role of substance P (SP) in these processes were examined in cultured alveolar macrophages (AM), type II epithelial cells (AIIE), and AM/AIIE co-cultures. Exposure of AM to JP-8 for 24 hr exhibited release of IL-1alpha,beta, whereas exposure to AIIE showed a concentration-dependent NO overproduction. Data indicate that there are cell-dependent inflammatory mechanisms responsible for the actual level of JP-8 exposure in alveoli. However, treatment with substance P significantly attenuated JP-8 induced the IL-1alpha,beta secretion. This finding was confirmed by using [Sar(9) Met (O(2))(11)] SP (10(- 10) M), an agonist of substance P, suggesting that substance P may have signal pathway(s) to AM in the inflammatory response mediated by IL-1. Moreover, AM/AIIE co-culture obviously reduced NO overproduction observed in AIIE alone, suggesting that there may be cell interactions or communications between AM and AIIE in response to the JP-8 exposure.