Objective:Exploring the changes in the expression of transient receptor potential vanilloid 1 (TRPV1) in the peripheral and central nervous system in rats temporomandibular joint osteoarthritis (TMJOA) and its relationship with TMJOA pain .Methods:From February 2024 to April 2025, 48 healthy male Sprague Dawley rats were randomly divided into a control group and an experimental group, with 24 rats in each group. The modeling periods for both groups were 2, 4, and 6 weeks, with 8 rats per group at each time point. After bilateral injection of monosodium iodoacetate (MIA) into the temporomandibular joint (TMJ) cavity to establish a TMJOA model, the TMJ condyle, trigeminal ganglion (TG), trigeminal nucleus caudate (TNC), and hippocampal tissue were collected. Pain threshold detector von Frey silk was used to evaluate the head withdrawal threshold (HWT) of rats, and HE staining and micro-CT scanning were used to observe the histological changes of TMJ. Immunohistochemical staining was used to detect the expression of TRPV1 in TG and hippocampal tissues, as well as the expression of glial fibrillar acidic protein (GFAP) in TNC.Results:On the first day after modeling, the HWT of rats significantly decreased and then gradually increased. From day 7 to day 14, HWT decreased again, and after day 14, HWT gradually increased. Statistically significant differences were observed between the experimental group and the control group at each time point ( P<0.001). HE staining and micro-CT revealed that in the second week after modeling, the arrangement of condylar bone trabeculae was disordered, the trabeculae became thinner, the bone marrow cavity became larger, and then the trabeculae became thicker and the bone marrow cavity became smaller. The number of TRPV1 positive cells in TG of TMJOA rats reached its peak in the second week of modeling, and then gradually decreased in the fourth and sixth weeks ( P<0.001), with no statistically significant difference in the control group ( P=0.941). The number of GFAP positive cells in TNCs of TMJOA rats significantly increased, reaching its peak in the second week of modeling and gradually decreasing in the fourth and sixth weeks ( P<0.001). There was no statistically significant difference between the control group ( P=0.720). The number of TRPV1 positive cells in the hippocampus of TMJOA rats significantly increased. The number of TRPV1 positive cells reached its peak in the second week of modeling, and then gradually decreased in the fourth and sixth weeks ( P<0.001). There was no statistically significant difference between the control group ( P=0.776). Conclusions:In the MIA induced rat TMJOA model, the expression of TRPV1 in TG and hippocampal tissue, as well as the expression of GFAP in TNC, were upregulated, which may be involved in the occurrence and development of TMJOA pain and related to the development of TMJOA lesions.

Objective:Exploring the changes in the expression of transient receptor potential vanilloid 1 (TRPV1) in the peripheral and central nervous system in rats temporomandibular joint osteoarthritis (TMJOA) and its relationship with TMJOA pain .Methods:From February 2024 to April 2025, 48 healthy male Sprague Dawley rats were randomly divided into a control group and an experimental group, with 24 rats in each group. The modeling periods for both groups were 2, 4, and 6 weeks, with 8 rats per group at each time point. After bilateral injection of monosodium iodoacetate (MIA) into the temporomandibular joint (TMJ) cavity to establish a TMJOA model, the TMJ condyle, trigeminal ganglion (TG), trigeminal nucleus caudate (TNC), and hippocampal tissue were collected. Pain threshold detector von Frey silk was used to evaluate the head withdrawal threshold (HWT) of rats, and HE staining and micro-CT scanning were used to observe the histological changes of TMJ. Immunohistochemical staining was used to detect the expression of TRPV1 in TG and hippocampal tissues, as well as the expression of glial fibrillar acidic protein (GFAP) in TNC.Results:On the first day after modeling, the HWT of rats significantly decreased and then gradually increased. From day 7 to day 14, HWT decreased again, and after day 14, HWT gradually increased. Statistically significant differences were observed between the experimental group and the control group at each time point ( P<0.001). HE staining and micro-CT revealed that in the second week after modeling, the arrangement of condylar bone trabeculae was disordered, the trabeculae became thinner, the bone marrow cavity became larger, and then the trabeculae became thicker and the bone marrow cavity became smaller. The number of TRPV1 positive cells in TG of TMJOA rats reached its peak in the second week of modeling, and then gradually decreased in the fourth and sixth weeks ( P<0.001), with no statistically significant difference in the control group ( P=0.941). The number of GFAP positive cells in TNCs of TMJOA rats significantly increased, reaching its peak in the second week of modeling and gradually decreasing in the fourth and sixth weeks ( P<0.001). There was no statistically significant difference between the control group ( P=0.720). The number of TRPV1 positive cells in the hippocampus of TMJOA rats significantly increased. The number of TRPV1 positive cells reached its peak in the second week of modeling, and then gradually decreased in the fourth and sixth weeks ( P<0.001). There was no statistically significant difference between the control group ( P=0.776). Conclusions:In the MIA induced rat TMJOA model, the expression of TRPV1 in TG and hippocampal tissue, as well as the expression of GFAP in TNC, were upregulated, which may be involved in the occurrence and development of TMJOA pain and related to the development of TMJOA lesions.

While human induced pluripotent stem cells (hiPSCs) have promising applications in regenerative medicine, most of the hiPSC lines available today are not suitable for clinical applications due to contamination with nonhuman materials, such as sialic acid, and potential pathogens from animal-product-containing cell culture systems. Although several xeno-free cell culture systems have been established recently, their use of human fibroblasts as feeders reduces the clinical potential of hiPSCs due to batch-to-batch variation in the feeders and time-consuming preparation processes. In this study, we have developed a xeno-free and feeder-cell-free human embryonic stem cell (hESC)/hiPSC culture system using human plasma and human placenta extracts. The system maintains the self-renewing capacity and pluripotency of hESCs for more than 40 passages. Human iPSCs were also derived from human dermal fibroblasts using this culture system by overexpressing three transcription factors-Oct4, Sox2 and Nanog. The culture system developed here is inexpensive and suitable for large scale production.
Cell Culture Techniques ; methods ; Cell Differentiation ; Cellular Reprogramming ; Culture Media ; Extracellular Matrix Proteins ; isolation & purification ; Female ; Fibroblasts ; cytology ; Humans ; Lentivirus ; genetics ; Placenta ; chemistry ; Pluripotent Stem Cells ; cytology ; metabolism ; Pregnancy ; Sodium Chloride ; chemistry ; Transcription Factors ; genetics