Apoptotic-related protein expression in the diaphragm and the effect of dopamine during inspiratory resistance loading.

Dopamine (DA) is a free radical scavenger that attenuates apoptosis. We studied the effects of normal saline (NS) and DA on diaphragm apoptotic protein expression following 60 min of inspiratory resistance loading in rats. We tested for 27 apoptotic-related proteins and found 12 in the diaphragm. Of the 12 proteins, superoxide dismutase copper zinc (SOD [CuZn]) and proprioceptive event related potential (PERP) were significantly higher in the DA group than in the NS and sham groups (p = .002, p = .007). DA group diaphragms had significantly greater expression of SOD (CuZn) than the NS (p = .005) and sham group diaphragms (p = .003). Likewise, the DA group had significantly greater expression of PERP than the NS group (p = .008). These results suggest that DA decreases diaphragm apoptosis through elevated expression of SOD (CuZn). The identification of 12 apoptotic-related proteins will assist investigators as they study diaphragm apoptosis.