When comparing serum cytokine concentrations , LPS-treated dogs had higher interleukin-6 ( IL-6 ) , IL-10 , TNF - and KC-like at 1 , 2 , and 4 hours ; higher CCL2 at 1 , 2 , 4 , and 24 hours ; and higher IL-8 and CXCL10 at 4 hours compared to placebo-treated dogs .