60Co-gamma ray can injure the chromesomes of bone marrow cells

and this injury may be measured by determining the rate of micronuclei of bone marrow cells of irradiated mice. Our observations indicated that the formation rate of micronuclei of bone marrow cells could decrease 472% if the mice had administered DNA from carp spermary (100 mg/kg weight) for 15 days before they were irradiated. Ultroviolet can damage DNA of cells. The damaged DNA can be repaired by the repair enzymes system in cells. The repairing speed can be measured by 3H-TdR intercalation (ie unscheduled DNA synthesis measurement

UDS measurement ). The results showed that the UDS of whole blood cells in mice had increased 4002% after DNA from carp spermary (30 mg/kg weight ) had been administered to the mice for 3 months.