TNF and arthritic joint disease: Furthermore, similar samples (equimolar amounts of RNA pooled from four—two male and two female—6-wk-old arthritic mice; severity index 3) of total RNA (from SF and WJ) from another animal model of arthritis (spontaneous, knock-in, TNF ΔARE+/-) [8] were used for additional chip hybridizations (four chipsets, eight chips total).