[Effects of tannic acid pretreatment on cardiovascular function during hemorrhagic shock in rats]

To investigate the effects of tannic acid pretreatment on cardiovascular function during hemorrhagic shock in rats.

Sprague-Dawley (SD) rats were randomly divided into two groups of shock and tannic acid pretreatment+shock. (1) In vivo experiment: the model of hemorrhagic shock in rats was reproduced by bleeding to 40 mm Hg (1 mm Hg = 0.133 kPa) being maintained for 120 minutes. Tannic acid in the dosage of 5 mg/kg was injected intravenously 10 minutes before hemorrhagic shock in tannic acid pretreatment+shock group. The mean arterial pressure (MAP), myocardial contractility and vascular reactivity were measured before hemorrhagic shock and at 180 minutes after hemorrhagic shock. In another experiment, the rats subjected to hemorrhagic shock and blood reinfusion were injected with norepinephrine (NE) intravenously at 60,120 and 180 minutes, and the vascular reactivity was observed. (2) In vitro experiment: the heart was harvested after shock and fixed on a Langendorff system. The perfusion pressure was maintained at 100 mm Hg. The effects of tannic acid pretreatment on myocardial contractility was observed.

(1)In vivo experiment showed that tannic acid pretreatment significantly increased MAP at 60 minutes and 150 minutes, and left ventricular systolic pressure (LVSP) at 60 minutes, and the heart rate was obviously slowed at 120 minutes, and left ventricular end diastolic pressure (LVEDP) was lowered (all P < 0.05). The vascular reactivity was significantly improved at 120 minutes in tannic acid pretreatment+shock group compared with shock group (P < 0.05). (2) In vitro experiment proved that tannic acid pretreatment significantly slowed heart rate at 90 minutes as well as increased +dp/dtmax at 10 minutes and 20 minutes and -dp/dtmax at 10 minutes (all P < 0.05).

Pretreatment with tannic acid improves cardiovascular function following hemorrhagic shock to some extent in rats.