Experimental Study On The Effect Of Hyperbaric Oxygen Therapy In Postirradiation Sialadenitis Of White Rats

Hwang, Hyo Yeon; Yoon, Jung Ho

Abstract

Main objectives of this study were to produce the experimental postirradiation sialadenitis and to observe the effects of hyperbaric oxygen therapy after the production of postirradiation sialadenitis in the unilateral parotid gland of white rats. To produce the experimental postirradiation sialadenitis, author attempted the various methods of irradiation such as 1000rad weekly for 5 weeks, or single dosage of 2000rad, 3000rad, 5000rad, but those attempts were futile due to the high mortality of experimental animals(used 80rats for pilot study). Finally author had to design fractional irradiation, that is, 1000rad per 2 weeks, total 5000rad for 8 weeks in order to produce postirradiation sialadenitis. The occurrence of postirradiation sialadenitis was proved with serial salivary scan findings. Author used irradiation 1000rats, dividing into the control(50) and experimental group (50) and rendered the hyperbaric oxygen therapy(2 hours/daily at 2.4ATM) on the experimental group for 6 weeks. The effect of hyperbaric oxygen therapy was examined by salivary scan findings and microscopic examination. The obtained results of this study were as follows: 1. The differences of salivary gland function between irradiated parotid glands(right) and nonirradiated parotid glands(left) showed the most remarkable changes at 32 weeks after total 5000rad irradiation. 2. In microscopic examination at 32 weeks after total 5000rad irradiation, irradiated parotid glands(right) showed severe degenerative changes of acinar cells, separations of lobules due to edema, severe intralobular fibrosis and connective tissue fibrosis. 3. After hyperbaric oxygen therapy for 4 weeks, the effect of hyperbaric oxygen therapy showed no distinctive difference findings between the control and the experimental group with salivary scan findings(p>or=0.05), while the experimental group showed progressive intralobular edema, copillary proliferation, hyperemia in connective tissues and intralobular fibrosis in microscopic examination. 4. Tc99m uptake of the experimental group was raised after hyperbaric oxygen therapy for 6 weeks, and showed reduction of Tc99m uptake ratio between irradiated parotid gland and nonirradiated gland up to 8 to 10 weeks(p<0.05), while in the microscopic exemination the experimental group showed aggravated acinar cell degeneration, intercalated duct proliferation, connective tissues fibrosis. In this study, author speculated that though the hyperbaric oxygen therapy improved the capillary impairment, there was a tendency to increase the degenerative changes of parechyma of postirradiated parotid glands, thus the usage of the hyperbaric oxygen therapy should be considered carefully in the aspect of hazardous effect to the parotid parenchymal tissues.