R M Nagler1. 1. Department of Oral and Maxillofacial Surgery, Rambam Medical Center, Haifa, Israel.
Abstract
BACKGROUND: Irradiation-induced salivary damage which results in severe xerostomia is a well known entity. However, the underlying mechanism of this phenomenon is still considered enigmatic. MATERIALS AND METHODS: We used one of the most studied models, male Wistar rats, and irradiated them to the head and neck region with both a low dose [2.5 Gy] and a high dose [15 Gy] of irradiation. Then we evaluated salivary gland function, weight and morphology of both parotid and submandibular glands in the same animals. Examinations were obtained for the short-term [3 days], long-term [40 days] and extended-term [90 days] time points. RESULTS: We found that irradiation with 15 Gy, but not 2.5 Gy, profoundly affected all salivary parameters evaluated, the parotid gland to a greater extent. At 40 days post- 15 Gy irradiation, parotid acini tissue was reduced by 35% [p < 0.01], being replaced by fibrovascular stromal tissue. This reduction was accompanied by parotid weight and function reduction of 27% [p < 0.05] and 58% [p < 0.01], respectively. At ninety days post-15 Gy irradiation, the parotid and submandibular functions were reduced by 84% [p < 0.01] and 62% [p < 0.01] respectively, while the gland weights were reduced by 62% [p < 0.01] and 39% [p < 0.01], respectively. CONCLUSION: The accumulated data demonstrate the time and dose dependent effects of irradiation on both parotid and submandibular glands. The effects were more profound for the parotid gland and a partial correlation between salivary hypofunction and parenchymal destruction was demonstrated.
BACKGROUND: Irradiation-induced salivary damage which results in severe xerostomia is a well known entity. However, the underlying mechanism of this phenomenon is still considered enigmatic. MATERIALS AND METHODS: We used one of the most studied models, male Wistar rats, and irradiated them to the head and neck region with both a low dose [2.5 Gy] and a high dose [15 Gy] of irradiation. Then we evaluated salivary gland function, weight and morphology of both parotid and submandibular glands in the same animals. Examinations were obtained for the short-term [3 days], long-term [40 days] and extended-term [90 days] time points. RESULTS: We found that irradiation with 15 Gy, but not 2.5 Gy, profoundly affected all salivary parameters evaluated, the parotid gland to a greater extent. At 40 days post- 15 Gy irradiation, parotid acini tissue was reduced by 35% [p < 0.01], being replaced by fibrovascular stromal tissue. This reduction was accompanied by parotid weight and function reduction of 27% [p < 0.05] and 58% [p < 0.01], respectively. At ninety days post-15 Gy irradiation, the parotid and submandibular functions were reduced by 84% [p < 0.01] and 62% [p < 0.01] respectively, while the gland weights were reduced by 62% [p < 0.01] and 39% [p < 0.01], respectively. CONCLUSION: The accumulated data demonstrate the time and dose dependent effects of irradiation on both parotid and submandibular glands. The effects were more profound for the parotid gland and a partial correlation between salivary hypofunction and parenchymal destruction was demonstrated.