Effects of hemorrhagic shock on nuclear DNA

Rats, with their liver DNA labeled with 3H-thymidine, were subjected to hemorrhagic shock. In nine rats reversible hemorrhagic shock with a blood pressure of 40 mm Hg for 30 minutes resulted in no breaks in the DNA. Twenty-seven animals were subjected to severe hemorrhagic shock. Blood pressures of 40 mm Hg were maintained in the 27 animals until 50% of the shed blood was infused in 11 animals and until 70% of the shed blood was reinfused in 16 animals. This degree of hemorrhage resulted in the DNA being broken, so that 45.1% and 52.1% of the DNA was of a small molecular weight species, as compared with 9.5% and 10.8% in the preshocked animals (P less than 0.001). The injured DNA was not repaired 1.5 hours after the animals were resuscitated in the animals subjected to severe hemorrhagic shock.