Biological Effects of Electromagnetic Pulse on Necroptosis of Mandibular Condylar Chondrocytes in Rats

doi:10.13701/j.cnki.kqyxyj.2021.11.014

Abstract

Abstract: Objective: To explore the biological effects of different high-intensity electromagnetic pulse (EMP) stimulation on mandibular condylar cartilage and the involvement of chondrocyte necroptosis, so as to provide new ideas for the protection and treatment of electromagnetic radiation in the future. Methods: SD rats were randomly divided into Sham group (SHAM group) and irradiation group (EMP1 group and EMP2 group), then were sacrificed at 3 h, 12 h, and 24 h after irradiation. The degree of cartilage degeneration was evaluated by HE staining, Safranin O staining, and type Ⅱ collagen staining. Immunohistochemistry and Western blotting were used to detect the expression of RIPK3 and p-MLKL in condylar cartilage. Results: Compared with SHAM group, a large number of chondrocytes in condylar hypertrophy layer of EMP1 group showed abnormal nuclei hyperchromatism and enlargement at 3 h, and the abnormal hyperchromatism almost disappeared at 12 h and 24 h. There was no significant change in cell morphology in EMP2 group. Compared with SHAM group, the percentage of type Ⅱ collagen positive area in condylar cartilage of EMP1 group was significantly lower (P<0.05). However, there was no significant difference in the percentage of type Ⅱ collagen positive area in EMP2 group (P>0.05). Compared with SHAM group, there was no significant difference in cartilage thickness and percentage of proteoglycan positive area in both EMP1 and EMP2 group (P>0.05). The percentage of positive chondrocytes and protein expression of RIPK3 and p-MLKL in condylar cartilage of EMP1 group were significantly higher than SHAM group at 3 h and 24 h (P<0.01), and with no significant difference from SHAM group at 12 h. In EMP2 group, the percentage of RIPK3 positive chondrocytes and protein expression were significantly decreased (P<0.01), the percentage of p-MLKL positive chondrocytes and protein expression were significantly increased at 3 h (P<0.05), there was no significant difference at 12 h and decreased significantly at 24 h (P<0.05). Conclusion: A certain dose of EMP can cause transient damage of condylar cartilage, in which necroptosis is involved in the transient effect of EMP on condylar cartilage.

Key words: electromagnetic radiation, electromagnetic pulse, condylar, cartilage, necroptosis

MA Yuanjun, HE Feng, WANG Jin, LIU Qian, CHEN Xiaohua, HE Rui, LI Tianle, TONG Xin, YU Shibin. Biological Effects of Electromagnetic Pulse on Necroptosis of Mandibular Condylar Chondrocytes in Rats[J]. Journal of Oral Science Research, 2021, 37(11): 1029-1035.

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