Aitasalo K
Acta Otolaryngol Suppl. 1986;428:1-54.
The present study was conducted on bone tissue responses to irradiation towards a treatment model of mandibular irradiation injury by comparing the results of experimental observations of irradiation effects on rabbit hind legs and rat mandibular bones (paper I, II and III) with clinical observations of irradiation effects on the human mandible (paper IV, V and VI). The main results of the study were as follows: Bone marrow haemorrhage, eosinophilia and incipient edema were encountered in the rabbit leg one day after a single irradiation dose. Edema and fibrosis were the salient features after five weeks, while both regenerative and fibrotic changes predominated eleven weeks after irradiation. The changes were the more extensive the greater the irradiation dose was. Empty lacunae as a sign of cell damage in cortical bone already appeared on the first day after irradiation; this effect reached its maximum when the dose was 20 Gy or more. Bone marrow and subcutaneous tissue pO2 and pCO2 were measured by means of implanted Silastic tonometers in irradiated and nonirradiated rabbit hind legs. Single dose irradiation was followed by a rapid, dose dependent decrease of marrow pO2. The corresponding effect on pCO2 was weaker and appeared later. The response to hyperoxia in the bone marrow became weaker when the irradiation dose increased. Less significant was the response of CO2 tension to hyperoxia. O2 and CO2 tensions were recovered after single dose irradiation both in subcutaneous tissue and in bone marrow, but the reduction was less in bone marrow. During the twelve weeks observation period clearly better recovery in tissue gas tensions was observed in subcutaneous tissue than in bone marrow. Nonirradiated periosteal grafts on irradiated bone cavities in the rabbit tibia induced more rapid and intense mature bone formation than irradiated periosteal grafts. The irradiated periosteum, even after a single dose of 20 Gy, had some osteogenetic capacity. The alkaline phosphatase content was lowered eight weeks after surgery in irradiated legs but clearly exceeded control values twelve weeks after surgery indicating new bone formation. Lysosomal enzyme DAP II contents were increased in all irradiated specimens as a sign of disturbed bone formation. The tissue concentrations of acid phosphatase, cytochrome oxidase, lactate dehydrogenase, isocitrate dehydrogenase, glucose-6-phosphate dehydrogenase and succinate dehydrogenase in the immediate postirradiation period showed a greater increase in activity in the cut lines of the irradiated rat mandibles than in those of the nonirradiated mandibles.(ABSTRACT TRUNCATED AT 400 WORDS)
本研究通过比较对兔后腿和大鼠下颌骨照射效果的实验观察结果（论文I、II和III）与对人类下颌骨照射效果的临床观察结果（论文IV、V和VI），对骨组织对辐射的反应进行了研究，以建立下颌骨辐射损伤的治疗模型。该研究的主要结果如下：单次照射剂量一天后，兔腿部出现骨髓出血、嗜酸性粒细胞增多和初期水肿。五周后，水肿和纤维化是主要特征，而照射十一周后，再生和纤维化变化均占主导。照射剂量越大，变化越广泛。皮质骨中作为细胞损伤标志的空骨陷窝在照射后第一天就已出现；当剂量达到20 Gy或更高时，这种效应达到最大值。通过植入硅橡胶张力计测量照射和未照射的兔后腿骨髓和皮下组织的pO₂和pCO₂。单次剂量照射后，骨髓pO₂迅速出现剂量依赖性下降。对pCO₂的相应影响较弱且出现较晚。照射剂量增加时，骨髓对高氧的反应变弱。CO₂张力对高氧的反应不太明显。单次剂量照射后，皮下组织和骨髓中的O₂和CO₂张力均恢复，但骨髓中的降低幅度较小。在十二周的观察期内，皮下组织中组织气体张力的恢复明显优于骨髓。在兔胫骨照射骨腔上的未照射骨膜移植物比照射骨膜移植物诱导更快、更强烈的成熟骨形成。即使单次剂量为20 Gy，照射后的骨膜仍具有一定的成骨能力。照射后腿术后八周碱性磷酸酶含量降低，但术后十二周明显超过对照值，表明有新骨形成。所有照射标本中溶酶体酶DAP II含量增加，表明骨形成受到干扰。照射后即刻，照射大鼠下颌骨切割线处酸性磷酸酶、细胞色素氧化酶、乳酸脱氢酶、异柠檬酸脱氢酶、葡萄糖-6-磷酸脱氢酶和琥珀酸脱氢酶的组织浓度活性增加幅度大于未照射下颌骨。（摘要截断于400字）
