Post-radiation treatment with IGF1 increases sphere-forming efficiency of irradiated parotid-derived cells.

<p>A single 5 Gy dose of radiation was given to 4–6 week old or 8 week female FVB mice followed by injections of insulin growth factor 1 (IGF1) on days 31–33 as depicted (A). Stimulated salivary flow rates were determined as described in the materials and methods section on day 60. The graph represents the mean saliva flow rate from 6 mice (8 week old) per treatment group: untreated control (UT), irradiated (IR d60), and IGF1 treated (IR-IGF1). Significant differences (*p<0.05) were determined using a one-way ANOVA followed by a post-hoc Tukey multiple comparison test (B). Thirty days following IGF1 treatment, parotid glands were collected for sphere formation assay. Representative graph of the average number (± SEM) of salispheres from 10 wells per treatment group on day 7 in culture from one IR d60 and IR+IGF primary sphere preparation (C). Representative bright field images of salispheres grown from irradiated (IR d60) and IGF1 treated (IR-IGF1) glands in serum-free media at different time points in culture (D). Irradiated (IR d60) and IGF1 (IR-IGF1) treated parotid-derived salispheres were fixed after 7 days in culture and stained for Ki-67 (green). Representative confocal immunofluorescence images are shown (E). Scale bar = 50μm.