Objective: To investigate the protective effect of hydrogen sulfide (H2S) on tissue factor-induced disseminated intravascular coagulation (DIC) in rabbits and its mechanism.
Methods: Thirty-two healthy rabbits were randomly divided into four groups: normal control group, NaHS control group, DIC model group, NaHS pretreatment group (each, n = 8). Ten minutes before model reproduction, rabbits in NaHS control and pretreatment groups were given 3.4 mg/kg NaHS (dissolved in normal saline to 5 mL) via ear vein, while rabbits in normal control and DIC model groups were given an equivalent volume of normal saline. Ten minutes later, rabbits in DIC model and NaHS pretreatment groups were intravenously given tissue factor (TF) 2 mL/kg (dissolved in normal saline to 30 mL, at the speed of 1 mL/min for 5 minutes, 2 mL/min for 5 minutes, and 3 mL/min for 5 minutes), and rabbits in normal control and NaHS control groups were given normal saline. 3 mL of blood was collected 10 minutes before TF injection, and 3, 5, 8, 10, 13, 15, 45, 85, 135 minutes after TF injection for determination of prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen content (FIB), fibrin degradation products (FDP), and platelet count (PLT). Microcirculation in the mesentery was also observed under microscope.
Results: Compared with normal control group, PT and APTT became shorter at 5 minutes after TF injection, and the rate of their change was increased [PT: -8.3 (-11.7 to -5.3)% vs. 1.3 (-2.5 to 3.8)%, P < 0.01; APTT: -19.1 (-30.4 to -9.4)% vs. -2.6 (-6.2 to 3.0)%, P < 0.05]. PT and APTT were prolonged 15 minutes after TF injection, and their changes were more significant [PT: 31.0 (25.0 to 36.9)% vs. -1.3 (-6.3 to 5.0)%, APTT: 61.3 (50.0 to 72.9)% vs. 0.0 (-10.0 to 10.0)%, both P < 0.01] in DIC model group. TT was gradually reduced after TF injection, FIB and PLT were gradually decreased, and their changes were more obvious at 15 minutes in DIC model group compared with those in normal control group [TT: -9.5 (-12.0 to -6.2)% vs. -2.0 (-4.0 to 0.7)%, FIB: -4.3 (-9.9 to -2.2)% vs. -1.0 (-5.8 to 4.3)%, PLT: -90.0 (-93.4 to -86.5)% vs. -1.0 (-3.9 to 2.6), all P < 0.01]. After TF injection, it appeared latex-like particles in FDP test board, and it was gradually increased within 3-15 minutes, and then it gradually became less marked. The rate of blood flow in mesenteric capillaries was decreased obviously within 10 minutes, and it became faster accompanying with obvious hemorrhage. PT and APTT in NaHS pretreatment group became shortened 5 minutes after TF injection, and their rate of change was significantly decreased compared with that of DIC model group [PT: -6.3 (-8.6 to 0.0)% vs. -8.3 (-11.7 to -5.3)%, APTT: -13.6 (-24.2 to -2.3)% vs. -19.1 (-30.4 to -9.4)%, both P < 0.05], and prolonged at 15 minutes, and their rate of change was significantly decreased compared with that of DIC model group [PT: 10.1 (3.8 to 15.2)% vs. 31.0 (25.0 to 36.9)%, P < 0.01; APTT: 27.8 (-15.8 to 39.7)% vs. 61.3 (50.0 to 72.9)%, P < 0.05]. TT, FIB, and PLT were reduced at 15 minutes in NaHS pretreatment group, and their rate of change was markedly decreased compared with that of DIC model group [TT: -4.5 (-7.8 to -1.3)% vs. -9.5 (-12.0 to -6.2)%, P < 0.01; FIB: -3.3 (-8.0 to 1.9)% vs. -4.3 (-9.9 to -2.2)%, P < 0.05; PLT: -58.8 (-53.0 to 64.0)% vs. -90.0 (-93.4 to -86.5)%, P < 0.01]. The rate of agglutination of latex particles in NaHS pretreatment group was decreased significantly at each time point compared with DIC model group; mesenteric capillary blood flow slowed down gradually within 10 minutes, but it was faster as compared with the DIC model group. It became faster later, but bleeding was obviously less.
Conclusions: These results show that H2S protects against TF-induced DIC by inhibiting the activity of coagulation system and platelet aggregation.