Change of salivary IgA secretion and caries development in irradiated rats.
Xerostomia is a serious side-effect of radiotherapy for head and neck cancer and often enhances caries activity. However, the relationship between caries induction and the IgA level in saliva in rats subjected to irradiation of the salivary glands is unclear. The effect of salivary gland irradiation on salivary function was examined in specific pathogen-free Sprague-Dawley rats infected with or without Streptococcus mutans MT8148R (serotype c). The flow rate of saliva and the protein concentration in saliva were significantly reduced in irradiated rats, regardless of infection of S. mutans. The caries activity was enhanced in these rats, and and irradiation level of 50 Gy significantly increased the caries score. However, longitudinal study indicated that the salivary concentration of IgA reactive with S. mutans whole cells maintained similar or significantly higher levels in irradiated rats, when compared with those of nonirradiated rats. In addition, there was no negative correlation between the caries score and the salivary concentration of IgA reactive with S. mutans. These findings suggest that the secreted IgA against S. mutans may not play a significant role in the caries induction of hyposalivated rats.
Takei
T
T
Department of Pedodontics, Faculty of Dentistry, Osaka University, Japan.
Aono
W
W
Nagashima
S
S
Yoshida
T
T
Hashida
T
T
Sobue
S
S
Ooshima
T
T
D000818:Animals; D003731:Dental Caries / Q000209:etiology* / Q000382:microbiology; D007071:Immunoglobulin A, Secretory / Q000032:analysis / Q000528:radiation effects*; D008137:Longitudinal Studies; D008297:Male; D011829:Radiation Dosage; D011833:Radiation Injuries, Experimental / Q000209:etiology* / Q000382:microbiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012469:Salivary Glands / Q000378:metabolism / Q000528:radiation effects*; D012471:Salivary Proteins and Peptides / Q000032:analysis / Q000528:radiation effects; D012636:Secretory Rate / Q000528:radiation effects; D013047:Specific Pathogen-Free Organisms; D013295:Streptococcus mutans / Q000502:physiology
D007071:Immunoglobulin A, Secretory; D012471:Salivary Proteins and Peptides