OBJECTIVETo observe the pathological changes and the expression of tumor necrosis factor alpha (TNF-alpha) and transforming growth factor beta (TGF-beta) in lung tissue of rats with radiation injury for exploring the mechanism of blood-activating and stasis-dissipating drugs in radiation injury prevention and treatment.

METHODSOne hundred and thirty SD female rats were randomly allocated into the simple irradiation group (n=60), the TCM herbs treatment group (n=60) and the blank control group (n=10). The right lung of all rats except those in the blank control group were irradiated by linear accelerator, 3 Gy each time, twice weekly, the maximum accumulated dose being 30 Gy. Ten rats in the two groups were randomly sacrificed at each of the 6 time points (1, 3, 5, 8, 12 and 26 weeks after repeated irradiation), their lung was harvested out, sliced and dyed with HE stain. The histological changes, levels of TNF-alpha and TGF-beta expression in the lung tissue were then observed by immunohistochemical technique.

RESULTSThe most serious acute radiation pneumonia was seen in the 5th week and pulmonary fibrosis was remarkable in the 26th week in the simple irradiation group, with the expressions of TNF-alpha and TGF-beta at different time phases enhanced significantly (P < 0.01). While in the TCM herbs treatment group, the pneumonia was milder, pulmonary fibrosis in late stage was not so obvious, and the expressions of TNF-alpha and TGF-beta significantly lower than those in the simple irradiation group (P < 0.01).

CONCLUSIONBlood-activating and stasis-dissipating drugs can inhibit expression of inflammation-inducing factors and fibrosis-inducing factors to lessen the inflammatory reaction of early radiation pneumonia, prolong the progression of radiation lung fibrosis, showing preventive and treating action on radiation lung injury.