Possible radioprotection of submandibular glands in gamma-irradiated rats using kaempferol: a histopathological and immunohistochemical study

Abstract

Background and purpose

Salivary gland damage remains a problem despite advances in radiotherapy schedules for head and neck cancer. Kaempferol, a natural flavonoid, found in several fruits and vegetables, is a good antioxidant. This study was designed to evaluate the possible protective effects of kaempferol on submandibular glands (SMGs) of rats exposed to fractionated gamma irradiation.

Materials and methods

Twenty-four male adult Wistar albino rats were included in this study and assigned to three groups (n = 8). Rats in group K received kaempferol orally in five doses at a dose of 10 mg/kg/2 days for 10 days. Meanwhile, rats in group R were subjected to fractionated whole-body gamma irradiation at a dose of 2 Gy/5 days/week for 2 weeks (20 Gy), and the KR group received kaempferol as group K and then was subjected to a fractionated whole-body gamma irradiation as group R. SMG samples were collected on days 1 and 7 after the last radiation session; and processed for histopathological and immunohistochemical investigations.

Results

The SMGs of group R showed focal atrophy and degeneration. Acini showed vacuolization and had pyknotic hyperchromatic nuclei. Striated ducts degenerated, shrunken, and were surrounded by empty spaces. The percentage of areas covered by cyclooxygenase-2 (COX-2) significantly increased, whereas the percentage of areas covered by proliferating cell nuclear antigen (PCNA) significantly decreased compared with those in group K. Cotreatment with kaempferol (group KR) partially preserved normal gland architecture where acinar vacuolation and degeneration were almost absent; however, some ducts degenerated. A significant decrease in the percentage of areas covered by COX-2 and a significant increase in the percentage of areas covered by PCNA were observed compared with those in group R.

Conclusions

Kaempferol has a possible radioprotective effect on the SMGs of rats exposed to fractionated gamma irradiation.

Keywords:

• Radiation
• kaempferol
• submandibular glands
• histopathology
• cyclooxygenase-2
• proliferating cell nuclear antigen

Disclosure statement

The authors declare no conflicts of interest.

Additional information

Notes on contributors

Salwa Farid Ahmed

Salwa Farid Ahmed, PhD, is an assistant professor at Health Radiation Research Department, National Centre for Radiation Research and Technology, Atomic Energy Authority, Nasr City, Cairo, Egypt.

Noura Mohammed Bakr

Noura Mohammed Bakr, PhD, is a lecturer in Oral and Dental Biology Department, Faculty of Dental Medicine for Girls, Al-Azhar University, Egypt.

Nora Abdelgawad

Nora Abdelgawad, PhD, is a lecturer in Oral Medicine, Periodontology, Diagnosis and Radiology Department, Faculty of Dental Medicine for Girls, Al-Azhar University, Egypt.

Dina W. Bashir

Dina W. Bashir, PhD, is a lecturer in Cytology and Histology Department, Faculty of Veterinary Medicine, Cairo University, Egypt.