back to contentsSequential Changes in the Normal Tongue of Golden
Hamster after Radiofrequency Hyperthermia：Scanning
Electron Microscopic Study of Vascular Casts
Hiroshi Tsurumaki，Yasushi Ohashi，Makoto Suzuki*
Second Department of Oral and Maxillofacial Surgery, School of Dentistry, Niigata University,
Laboratory for clincal investigation, Niigata University Dental Hospital*
Abstract:
The purpose of this study was to identify sequential histological alterations and changes in the vascular system in normal tongue of golden hamsters following hyperthermia treatment.
Adult golden hamsters of both sexes were divided into 2 heated groups and a control group. The tongue was heated with a 13.56MHz radiofrequency (RF) capacitive heating system. In the 2 heated groups, the inside of the tongue was heated to 42.0℃and 43.0℃, respectively, for 40 minutes. Histological changes were investigated by light microscopy, and vascu1ar changes were observed by scanning electron microscopy of vascular casts.
The results were as follows;
l. Histologically, in the 42℃ treated group, changes such as relatively mild edema, capillary dilatation, and congestion were observed, but there was almost complete recovery within 48 hours. In the 43℃ treated group, however, severe congestion, interstitial edema, focal hemorrhage and capillary rupture occurred immediately after heating, and interstitial fibrosis was present 4 weeks after heating.
2. Scanning electron microscopic examination in the 42℃ treated group showed avascular areas where the resin was not present in part of the tongue surface within 24 hours, but this was no longer observed 48 hours after heating. In the 43℃ treated group, there were every extensive avascular areas in the heated area from immediately after heating up to 48 hours later, and morphologic irregularities in the vascular network were observed 1 week after heating.
3．These results indicate that transient vascular injury may occur as a result of 42℃ hyperthermia, but that severe circulatory impairment and irreversible vascular injury occur when normal vessels are exposed to 43℃ hyperthermia.
4. This tongue model was very useful for observing vascular injury induced by hyperthermia.