TGF-β3 increases the severity of radiation-induced oral mucositis and salivary gland fibrosis in a mouse model

Abstract

Purpose

Toxicities from head and neck (H&N) radiotherapy (RT) may affect patient quality of life and can be dose-limiting. Proteins from the transforming growth factor beta (TGF-β) family are key players in the fibrotic response. While TGF-β1 is known to be pro-fibrotic, TGF-β3 has mainly been considered anti-fibrotic. Moreover, TGF-β3 has been shown to act protective against acute toxicities after radio- and chemotherapy. In the present study, we investigated the effect of TGF-β3 treatment during fractionated H&N RT in a mouse model.

Materials and methods

30 C57BL/6J mice were assigned to three treatment groups. The RT + TGF-β3 group received local fractionated H&N RT with 66 Gy over five days, combined with TGF-β3-injections at 24-hour intervals. Animals in the RT reference group received identical RT without TGF-β3 treatment. The non-irradiated control group was sham-irradiated according to the same RT schedule. In the follow-up period, body weight and symptoms of oral mucositis and lip dermatitis were monitored. Saliva was sampled at five time points. The experiment was terminated 105 d after the first RT fraction. Submandibular and sublingual glands were preserved, sectioned, and stained with Masson’s trichrome to visualize collagen.

Results

A subset of mice in the RT + TGF-β3 group displayed increased severity of oral mucositis and increased weight loss, resulting in a significant increase in mortality. Collagen content was significantly increased in the submandibular and sublingual glands for the surviving RT + TGF-β3 mice, compared with non-irradiated controls. In the RT reference group, collagen content was significantly increased in the submandibular gland only. Both RT groups displayed lower saliva production after treatment compared to controls. TGF-β3 treatment did not impact saliva production.

Conclusions

When repeatedly administered during fractionated RT at the current dose, TGF-β3 treatment increased acute H&N radiation toxicities and increased mortality. Furthermore, TGF-β3 treatment may increase the severity of radiation-induced salivary gland fibrosis.

Keywords:

• Fibrosis
• head and neck cancer
• radiotherapy
• radiotoxicity
• transforming growth factor beta 3

Acknowledgements

We thank Delmon Arous at the Department of Physics, University of Oslo for help with the dosimetry measurements.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are openly available in Zenodo at http://doi.org/10.5281/zenodo.8337804

Additional information

Funding

This work was supported by UiO Life Science at the University of Oslo under grant reference [2018/10221] and South-Eastern Norway Regional Health Authority under grant number [2019050].

Notes on contributors

Ingunn Hanson

Ingunn Hanson is a PhD Research Fellow at the Biophysics and Medical Physics group at the University of Oslo, Norway. Her work is focused on low-dose radiation and the effects of TGF-β3 in radiation response.

Inga Solgård Juvkam

Inga Solgård Juvkam received a Master’s degree in Molecular Biosciences and a Bachelor’s degree in Biochemistry at the Institute of Biosciences at the University of Oslo. She is a PhD Research Fellow at the Institute of Oral Biology at the University of Oslo. She has experience in histology, cell biology, and preclinical experiments.

Olga Zlygosteva

Olga Zlygosteva is a PhD Research Fellow at the Biophysics and Medical Physics group at the University of Oslo, Norway. Her research interests include normal tissue effects and cytokine response after proton versus conventional radiotherapy of head and neck cancers.

Tine Merete Søland

Tine Merete Søland, PhD, is an associate professor in oral pathology at the Institute of Oral Biology, University of Oslo, Norway. In addition, she works as an oral pathologist in the diagnostic service at the Department of Pathology at Oslo University Hospital.

Hilde Kanli Galtung

Hilde Kanli Galtung, PhD, is a professor in physiology at the Institute of Oral Biology, Faculty of Dentistry, University of Oslo, Norway. Her scientific interest is salivary gland biology with special focus on cellular changes induced by conditions such as autoimmune disease and radiation damage.

Eirik Malinen

Eirik Malinen holds a PhD in physics (biophysics) and is Head of Department of Radiation Biology, Oslo University Hospital, and Professor at the Department of Physics, University of Oslo, Norway. He is engaged in radiation physics research as well as preclinical and clinical investigations utilizing ionizing radiation.

Nina Frederike Jeppesen Edin

Nina Jeppesen Edin, PhD, is an associate professor and head of Section for Biophysics and Medical Physics at the University of Oslo. Edin’s main interest is preclinical studies of biological effects and mechanisms induced by radiation of different qualities and deliveries.