The effect of salivary gland-derived stem cell transplantation on the regeneration of gamma-irradiated rat submandibular salivary glands: an immunohistochemical study

Abstract

Background Hyposalivation could be a sequela of radiation impairment in patients with head and neck cancer. Regenerative approaches based on the reactivation of endogenous stem cells or the transplant of exogenous stem cells hold substantial promise in restoring the structure and function of these organs to improve patient quality of life. Recently, tissue-specific stem cell therapy has attracted public attention as a next-generation therapeutic reagent. The aim of this work is to assess the regenerative potential of salivary gland-derived stem cells transplantation in gamma-irradiated rat submandibular salivary glands (SMSGs). Materials and methods Forty-six adult male albino rats were used in this study. Both SMSGs were harvested from five healthy donor rats and used as a source of stem cells. Cells were cultured for 3 and 10 days. Characterization and assessment of stemness after isolation by flow cytometry was carried out using CD24 stem cell marker by fluorescent analysis cell sorting. The rats were grouped as follows: group I (normal untreated control), group II (irradiation group), and group III (irradiation and transplantation group). They were subjected to whole-body gamma radiation with a single dose of 6 Gy. Results Stem cells were successfully isolated from rat SMSGs with positively expressing CD24 and C-kit markers. The statistical analysis revealed significant increase in cell proliferation (proliferating cell nuclear antigen) in both groups II and III compared with the control group I (P˂0.05). Regarding caspase 3 results, the statistical analysis revealed highly significant increase in the mean values of groups II and subgroups III compared with the control group I (P˂0.05). Concerning C-kit expression, group III showed the highest statistically significant mean C-kit expression, followed by group II and group I (P˃0.05). At 2 weeks after transplantation, group II showed the highest statistically significant mean C-kit expression followed by III and control group I (P˃0.05). Conclusion Transplantation of these C-kit+ submandibular salivary gland stem cell (SMSGSCs) could result in amelioration of the severely reduced quality of life of surviving patients with cancer.