The effect of a dietary phase 2 protein inducer on inflammatory parameters in blood and liver of spontaneously hypertensive stroke prone rats

Abstract

Inflammatory diseases such as hypertension are associated with high levels of oxidative stress. Characteristic of oxidative stress is the inflammatory acute phase protein response. Oxidative stress and its accompanied inflammation can be reduced via phase 2 enzyme induction. Broccoli sprouts, a rich source of phase 2 enzyme inducers such as isothiocyanates, can be incorporated into the diet to increase phase 2 enzymes. The hypothesis of this study is that, the dietary intake of dried broccoli sprouts, by inducing liver phase 2 enzymes, will decrease oxidative stress and the acute phase response in the blood of spontaneously hypertensive stroke-prone rats. Spontaneously hypertensive stroke-prone rats (SHRsp) and Sprague Dawley (SD) rats were placed either on a control diet of modified AIN-93G or an experimental diet of modified AIN-93G supplemented with dried broccoli sprouts. The following parameters were examined: 1. Isothiocyanate absorption (an increased level of dithiocarbamates is reflective of ITC absorption), 2. Oxidative stress (a reduction in oxidative stress is evidenced by an increase in plasma protein thiols and blood glutathione (GSH)), 3. Acute phase proteins (a decreased APR is reflected by an increase in plasma albumin and a decrease in ceruloplasmin), 4. Activity of phase 2 enzymes (increased phase 2 enzyme induction results in higher activities of liver quinone reductase (QR), glutathione-S-transferase (GST) and glutathione reductase (GR)). My experimental results demonstrated that broccoli sprout feeding results in higher protein thiol levels in female SHRsp and higher blood GSH levels in males but no acute phase protein changes were observed in either male or female SHRsp. Broccoli sprout feeding caused higher QR and lower GST activities in female SHRsp but did not affect the activities of phase 2 enzymes in male SHRsp. The activities of GST and QR were higher in SD rats than in SHRsp. Levels of dithiocarbamates were higher in the broccoli fed group than in the control fed group. The results from this study do not present a clear pattern to support the hypothesis that dietary intake of broccoli sprouts by inducing phase 2 enzymes will decrease parameters of oxidative stress and the acute phase response. In conclusion, there is an interactive role played by animal gender and the induction of phase 2 enzymes by dried broccoli sprouts.