Optimum dose range for the amelioration of long term radiation-induced hyposalivation using prophylactic pilocarpine treatment.
BACKGROUND
To determine dose and time dependency of pilocarpine pre-treatment protection from late damage after unilateral irradiation of the rat parotid gland.


METHODS
The right parotid gland of saline (1mg/ml) or pilocarpine (4 mg/kg) pre-treated rats was irradiated with 10, 15 and 20 Gy. Saliva was collected from the irradiated and shielded parotid before, 30, 60, 120 and 240 days after irradiation. The number of acinar cells/gland was determined 30, 120 and 240 days after irradiation by histological examination.


RESULTS
Pilocarpine pre-treated rats, protection of parotid gland function was seen in the early-intermediate phase (0-120 days) after 15 Gy and in the late phase (>120 days) after 10 and 15 Gy. Although no protection was observed after 20 Gy, a stimulatory effect of pilocarpine on the non-irradiated gland resulted in a significant increase in total saliva secretion. The increase in function after pilocarpine treatment was paralleled by a significant increase in the number of acinar cells in both the irradiated and shielded glands.


CONCLUSIONS
Pre-irradiation treatment with pilocarpine induces compensatory response, at lower doses, in the irradiated and at higher doses in the non-irradiated gland reducing late damage, due to stimulation of unirradiated or surviving cells to divide.
Burlage
Fred Ronald
FR
Department of Radiation Oncology, University of Groningen, The Netherlands. f.r.burlage@rt.umcg.nl
Roesink
Judith M
JM
Faber
Hette
H
Vissink
Arjan
A
Langendijk
Johannes A
JA
Kampinga
Harm H
HH
Coppes
Rob P
RP
D000818:Animals; D008297:Male; D018727:Muscarinic Antagonists / Q000008:administration & dosage*; D010306:Parotid Gland / Q000187:drug effects* / Q000473:pathology / Q000528:radiation effects*; D010862:Pilocarpine / Q000008:administration & dosage*; D011833:Radiation Injuries, Experimental / Q000517:prevention & control; D051381:Rats; D017208:Rats, Wistar; D012472:Salivation / Q000187:drug effects / Q000528:radiation effects; D014987:Xerostomia / Q000188:drug therapy* / Q000209:etiology
D018727:Muscarinic Antagonists; D010862:Pilocarpine