OBJECTIVETo investigate the influence of myocardial inhibition on injury to liver, kidney and intestine and blood perfusion at early stage in rat with severe burn.

METHODSThirty-two healthy male Wistar rats were enrolled in the study and randomly divided into sham scald, propranolol, scald control and scald + propranolol groups, with 8 rats in each group. After intraperitoneal injection of 10 g/L pentobarbital sodium for anesthesia, rats of the former two groups were sham scalded in a water bath of 37 degrees C for 18 s, while the latter two groups were inflicted with 30% TBSA full-thickness scald in a 97 degrees C water bath for 18 s. Rats were resuscitated with Ringer's lactate solution (4 mL x kg(-1) x 1% TBSA(-1), i. p.) following the Parkland formula 30 mins after the injury. At the same time, rats in propranolol and scald + propranolol groups received propranolol 0.75 mg/kg intravenously. After 6 hours, parameters of myocardiac mechanics (SBP, DBP, MAP, LVSP, LVEDP, +/- dp/dt max) were recorded by the multiple channel physiological signal collecting and processing system; blood flow of liver, kidney and intestine were detected with the laser doppler flowmetry; the serum contents of cTnI, TBA, beta2-MG and DAO were determined for reflecting injuries to the heart, liver, kidney and intestine, respectively.

RESULTSMyocardiac mechanics parameters, with the exception of LVEDP, were decreased in propranolol group as compared with those in sham group (P <.05). All myocardiac mechanics parameters in burn control group were lower than those in sham group and higher than those in burn + propranolol group (P < 0.05). Blood flow of organs showed similar changes in above-mentioned 3 groups (P < 0.05). Organ damages as shown in burn control group [cTnI (4.86 +/- 0.29) microg/L, TBA (83.6 +/- 18.2) micromol/L, beta2-MG (2.75 +/- 0.19) mg/L, DAO (1.45 +/- 0.09) x 10(3) U/L] were more serious than those in sham control group [cTnI (1.73 +/- 0.09) microg/L, TBA (24.5 +/- 2.4) micromol/L, beta2-MG (1.15 +/- 0.18) mg/L, DAO (0.87 +/- 0.13) x 10(3) U/L], and less serious than those in scald + propranolol group [cTnI 5.95 +/- 0.42 microg/L, TBA 125.8 +/- 21.3 micromol/L, beta2-MG 3.25 +/- 0.17 mg/L, DAO (1.83 +/- 0.13) x 10(3) U/L] (P < 0.05).

CONCLUSIONSPropranolol can aggravate injury to the liver, kidney and intestine at early stage in rat with severe burn, suggesting that "shock heart" may be one of initial factors in lowering blood flow to the organs, thus inducing injury to them.