Alpha lipoic acid attenuates radiation-induced thyroid injury in rats.
Exposure of the thyroid to radiation during radiotherapy of the head and neck is often unavoidable. The present study aimed to investigate the protective effect of α-lipoic acid (ALA) on radiation-induced thyroid injury in rats. Rats were randomly assigned to four groups: healthy controls (CTL), irradiated (RT), received ALA before irradiation (ALA + RT), and received ALA only (ALA, 100 mg/kg, i.p.). ALA was treated at 24 h and 30 minutes prior to irradiation. The neck area including the thyroid gland was evenly irradiated with 2 Gy per minute (total dose of 18 Gy) using a photon 6-MV linear accelerator. Greater numbers of abnormal and unusually small follicles in the irradiated thyroid tissues were observed compared to the controls and the ALA group on days 4 and 7 after irradiation. However, all pathologies were decreased by ALA pretreatment. The quantity of small follicles in the irradiated rats was greater on day 7 than day 4 after irradiation. However, in the ALA-treated irradiated rats, the numbers of small and medium follicles were significantly decreased to a similar degree as in the control and ALA-only groups. The PAS-positive density of the colloid in RT group was decreased significantly compared with all other groups and reversed by ALA pretreatment. The high activity index in the irradiated rats was lowered by ALA treatment. TGF-ß1 immunoreactivity was enhanced in irradiated rats and was more severe on the day 7 after radiation exposure than on day 4. Expression of TGF-ß1 was reduced in the thyroid that had undergone ALA pretreatment. Levels of serum pro-inflammatory cytokines (TNF-α, IL-1ß and IL-6) did not differ significantly between the all groups. This study provides that pretreatment with ALA decreased the severity of radiation-induced thyroid injury by reducing inflammation and fibrotic infiltration and lowering the activity index. Thus, ALA could be used to ameliorate radiation-induced thyroid injury.
Department of Internal Medicine, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea; Institute of Health Science, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea.
Jung Hwa
JH
Jung
Department of Internal Medicine, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea; Institute of Health Science, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea.
Jaehoon
J
Jung
Department of Internal Medicine, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea; Institute of Health Science, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea.
Soo Kyoung
SK
Kim
Department of Otolaryngology, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea; Institute of Health Science, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea.
Seung Hoon
SH
Woo
Department of Radiation Oncology, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea; Institute of Health Science, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea.
Ki Mun
KM
Kang
Department of Radiation Oncology, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea; Institute of Health Science, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea.
Bae-Kwon
BK
Jeong
Biomedical Research Institute, Gyeongsang National University Hospital, Jinju, Gyeongnam, Republic of Korea.
Myeong Hee
MH
Jung
Biomedical Research Institute, Gyeongsang National University Hospital, Jinju, Gyeongnam, Republic of Korea; Institute of Health Science, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea.
Jin Hyun
JH
Kim
Department of Internal Medicine, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea; Institute of Health Science, Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea.
Jong Ryeal
JR
Hahm
D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000494:pharmacology*; D016207:Cytokines / Q000097:blood / Q000378:metabolism; D004195:Disease Models, Animal; D005355:Fibrosis; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects; D011832:Radiation Injuries / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D011833:Radiation Injuries, Experimental; D011837:Radiation-Protective Agents / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D008063:Thioctic Acid / Q000008:administration & dosage / Q000494:pharmacology*; D013961:Thyroid Gland / Q000187:drug effects* / Q000473:pathology / Q000528:radiation effects*
D000975:Antioxidants; D016207:Cytokines; D011837:Radiation-Protective Agents; D008063:Thioctic Acid