Objective:The aim of this study is to explain the key role of chondrocyte ferroptosis in TMJ OA and demonstrate that abnormal occlusion stimulation is an important causative factor of ferroptosis.Methods:We observed the morphological changes of mouse condylar cartilage in unilateral anterior crossbite(UAC,an abnormal occlusion stimulation)and bilateral anterior elevation(BAE,a proliferation occlusion stimulation)mice by HE and SO staining,and analyzed the expression of intracellular GPX4 by im-munofluorescence staining,and analyzed the changes in the content of mitochondria and reactive oxygen species by JC-1 and ROS staining.Results:The UAC caused degeneration of condylar cartilage and ferroptosis of chondrocytes in mice.The accumulation of iron ions and the dysfunction of mitochondria in chondrocytes significantly upregulated.The expression of GPX4,which is a key reg-ulator in the regulation of ferroptosis was lowered in UAC mice condyle cartilage.Moreover,in BAE model the condylar cartilage hy-perplasia was observed,but not the ferroptosis of chondrocytes.Conclusion:This study revealed that the abnormal biological force caused by abnormal occlusion could induce ferroptosis of chondrocytes,and ferroptosis is one of the main factors leading to the de-generation and thinning of condylar cartilage.GPX4 could regulate the ferroptosis of chondrocytes.

Objective:The aim of this study is to explain the key role of chondrocyte ferroptosis in TMJ OA and demonstrate that abnormal occlusion stimulation is an important causative factor of ferroptosis.Methods:We observed the morphological changes of mouse condylar cartilage in unilateral anterior crossbite(UAC,an abnormal occlusion stimulation)and bilateral anterior elevation(BAE,a proliferation occlusion stimulation)mice by HE and SO staining,and analyzed the expression of intracellular GPX4 by im-munofluorescence staining,and analyzed the changes in the content of mitochondria and reactive oxygen species by JC-1 and ROS staining.Results:The UAC caused degeneration of condylar cartilage and ferroptosis of chondrocytes in mice.The accumulation of iron ions and the dysfunction of mitochondria in chondrocytes significantly upregulated.The expression of GPX4,which is a key reg-ulator in the regulation of ferroptosis was lowered in UAC mice condyle cartilage.Moreover,in BAE model the condylar cartilage hy-perplasia was observed,but not the ferroptosis of chondrocytes.Conclusion:This study revealed that the abnormal biological force caused by abnormal occlusion could induce ferroptosis of chondrocytes,and ferroptosis is one of the main factors leading to the de-generation and thinning of condylar cartilage.GPX4 could regulate the ferroptosis of chondrocytes.

Objective:To improve the prevention and treatment of venomous snake bites by analyzing the epidemiological characteristics of venomous snake bite in Wuzhou City, Guangxi Zhuang Autonomous Region.Methods:A retrospective analysis was conducted. The medical records of 1 091 patients with venomous snake bites admitted to the department of snake wound of Wuzhou Hospital of Traditional Chinese Medicine from January 2014 to December 2020 were collected, including snake species, gender and age of patients, bite time, bite site and local symptom.Results:The medical records of 952 patients with a definite clinical diagnosis of snake bite were enrolled. Among the 952 patients with venomous snake bites, the main bites were from Ovophis (32.98%), Trimeresurus (27.84%) and Naja (26.26%), followed by Bungarus multicinctus (6.51%), Ophiophagus Hannah (3.15%) and Agkistrodonhalys (1.58%), and few bites were from Rhabdophis subminiatus (0.73%), Bungarus fasciatus (0.42%), viper (0.32%) and Agkistrodon (0.21%). Of the 952 patients with venomous snake bites, there were almost twice as many males as females [647 cases (67.96%) vs. 305 cases (32.04%), with male to female ratio of 2.12∶1]. The age of patients ranged from 0.8 to 87.0 years old, with 40-59 years old as the majority (42.44%), followed by ≥ 60 years old (27.31%). Snake bites mainly occurred from April to November (93.59%), with a peak in October (16.39%). The incidence time was mainly afternoon (12:00-17:59, 30.88%) and evening (18:00-23:59, 33.30%), followed by morning (06:00-11:59, 24.69%), and early in the morning (00:00-05:59, 11.13%). The incidence time of Ovophis and Bungarus multicinctus mainly concentrated in 18:00-23:59, the time of Trimeresurus was in 06:00-11:59, and that of Naja and Ophiophagus hannah was in 12:00-17:59. Most cases of snake bite were on limbs (98.53%), and mainly on the right limbs (53.57%). The lower limbs mainly were bitten by Ovophis, while the upper limbs mainly were bitten by Naja and by Ophiophagus hannah. The local symptoms of the bite of Ovophis and Trimeresurus were similar, mainly including pain, swelling, tenderness, high temperature of skin around the wound, bleeding and exudation, etc. And the local symptoms of the bite of Naja were pain, swelling, bruising, tenderness, bleeding and exudation, red skin, etc. Numbness and mild pain were the main symptoms of the bite of Bungarus multicinctus and Bungarus fasciatus, but other local characteristics were not obvious.Conclusions:The majority of venomous snake bite patients in Wuzhou City of Guangxi were middle-aged and elderly males, and the majority of venomous snakes were Ovophis, Trimeresurus, and Naja. Most venomous snake bite occurs from April to November, and the incidence time was concentrated between 12:00 and 23:59. The majority of venomous snake bite was limb bites. The local symptoms were pain, swelling, tenderness, high temperature of skin around the wound, bruising, etc. To reduce the incidence rate, disability rate and mortality of snake bite disease, a snake bite prevention system should be established, the education and publicity of snake bite prevention knowledge should be strengthened, the awareness of snake bite prevention should be improved, and clinical diagnosis and treatment should be assisted, based on the epidemiological characteristics of snake bite in Wuzhou area.