UVC radiation-induced effect on human primary thyroid cell proliferation and HLA-DR expression

Area of Science:

• Immunology
• Cell Biology
• Biochemistry

Background:

• Ultraviolet C (UVC) irradiation is known to affect cellular processes.
• The role of UVC in thyroid cell function and its potential link to autoimmune thyroid diseases (AITD) requires further investigation.

Purpose of the Study:

• To investigate the effects of UVC irradiation on normal human thyroid cell proliferation and HLA-DR expression.
• To explore the involvement of oxidative stress and apoptosis in UVC-induced thyroid cell damage.

Main Methods:

• Primary human thyroid cells were exposed to UVC (254 nm).
• Buthionine sulfoximine (BSO), a glutathione synthesis inhibitor, was used to induce oxidative stress.
• Apoptosis was assessed using Annexin V, immunoblot analysis of apoptotic proteins (p53, Bax, Bcl-2, caspase 3, and 9), and cell cycle analysis.
• HLA-DR expression was measured by Flow Cytometry (FACS).

Main Results:

• UVC induced cell cycle arrest in G0/G1 phase and subsequent accumulation in S phase, leading to increased apoptosis.
• BSO pretreatment enhanced and accelerated apoptosis, suggesting a role for oxidative stress.
• UVC irradiation altered the expression of apoptosis-related proteins (increased p53, caspase 3, 9; decreased Bax, Bcl-2).
• A transient increase in HLA-DR expression was observed following UVC exposure.

Conclusions:

• UVC irradiation inhibits normal human thyroid cell proliferation and induces apoptosis through the intrinsic mitochondrial pathway.
• Oxidative stress appears to play a significant role in UVC-induced thyroid cell apoptosis.
• The transient increase in HLA-DR expression post-UVC irradiation may be implicated in the pathogenesis of autoimmune thyroid diseases.