Endoplasmic reticulum stress regulates rat mandibular cartilage thinning under compressive mechanical stress.

Compressive mechanical stress-induced cartilage thinning has been characterized as a key step in the progression of temporomandibular joint diseases, such as osteoarthritis. However, the regulatory mechanisms underlying this loss have not been thoroughly studied. Here, we used an established animal model for loading compressive mechanical stress to induce cartilage thinning in vivo.

[Effect of asymmetry elastic on the maturation of bone collagen and mineralization in condyle of adult SD rat].

Purpose: The aim of this investigation was to study the osteogenesis activation following asymmetric inter-maxillary elastic on the subchondral bone of adult SD rats.

Methods: Twenty SD ten-week old rats were used in this study (eight rats loading 0.39 N elastic force, another eight rats loading 1.

[Study on the method of two dimensional polycrylamide gel electrophoresis on rat condylar chondrocyte].

Purpose: To investigate the protein profile by two dimensional polycrylamide gel electrophoresis on the rat condylar chondrocyte in vitro.

Methods: The third-passage chondrocytes were harvested from the mandibular condyles of 2-day-old rats in this study. The protein profile of the rat mandibular condylar chondrocytes was examined by two dimensional polycrylamide gel electrophoresis (2-DE-PAGE).

Proteomic analysis of early-response to mechanical stress in neonatal rat mandibular condylar chondrocytes.

The objectives of this study were to investigate the early response to mechanical stress in neonatal rat mandibular chondrocytes by proteomic analysis. To evaluate its molecular mechanism, chondrocytes were isolated and cultured in vitro, then loaded mechanical stress by four-point bending system on different patterns. Morphological observation, flow cytometric analysis, and MTT assays indicated that 4,000 microstrain loading for 60 min was an appropriate mechanical stimulus for the following proteome analysis, which produced a transient but obvious inhibitory effect on the cell cycle.

[Effect of asymmetry traction on the expression of type II collagen in adult rat condyle].

Objective: The aim of this investigation was to study the expression of collagen type II in the cartilage of mandibular condyle following asymmetric inter-maxillary traction.

Methods: Two hundred and twenty SD rats were used in this study (one hundred and four rats loading 0.39 N elastic force, another one hundred and four rats loading 1.

[Early effects of the cyclic uniaxial compressive stress on Actin and Vimentin of the rat condylar chondrocytes].

Objective: To investigate the early effects of the cyclic uniaxial compressive stress on Actin and Vimentin of the rat condylar chondrocyte.

Methods: The third-passage chondrocyte were harvested from the mandibular condyles of 2-day-old rats, and a cellular compressive stress device was used to apply stress on cells at 4 000 microstrain for 15, 30, 60, 120, 240 min. The early effects of the cyclic uniaxial compressive stress on Actin and Vimentin of the rat mandibular condylar chondrocytes were examined by laser scanning confocal microscope (LSCM), immunofluorescence technique and Western blot.

[Early-response of the condylar chondrocyte under cyclic uniaxial compressive stress].

Objective: To investigate the protein profile after treatment of the cyclic uniaxial compressive stress on the rat condylar chondrocyte in vitro.

Methods: The third-passage chondrocytes were harvested from the mandibular condyles of 2-day-old rats, and a cellular compressive stress device (self-made four-point bending system) was used to apply stress on cells at 2000 microstrain and 4000 microstrain (0.5 Hz frequency) for 60 min.

[Early effects of the cyclic uniaxial compressive stress on Stress70/GRP75 in the rat condylar chondrocytes].

Purpose: The purpose of this study was to investigate the early effects of the cyclic uniaxial compressive stress on Stress70/GRP75 in the rat condylar chondrocyte.

Methods: The third-passage chondrocytes were harvested from the mandibular condyles of 2-day-old rats for this study, and a cellular compressive stress device (self-made four-point bending system, Patent No.01129166.

[The effect of Class III intermaxillary orthopedic force loading on the maxilla of puberty rhesus: a histomorphologic study].

Purpose: The purpose of this study is to quantitatively study the remodling changes of circummaxillary sutures of puberty rhesus loaded with Class III intermaxillary orthopedic force.

Methods: The animal model was established with 6 puberty female rhesus, which were randomly divided into experimental group (wore Class III Twin-block magnet appliance, each 2 rhesus for 3 and 6 months respectively) and control group(did not wear any appliance, each 1 rhesus for 3 and 6 months respectively ). The specimens were stained by hematoxylin and eosin, and image analysis system (IAS) was used in the quantatitive study of sutures width and cell density.

[Novel mutations of PAX9 gene in Chinese patients with oligodontia].

Objective: To investigate the mutational characteristics of PAX9 gene in Chinese patients with congenital oligodontia and thus to provide a molecular basis for studying the pathogenesis of oligodontia.

Methods: Thirteen individuals with oligodontia and 9 healthy individuals, from 4 unrelated autosomal dominant families, and 16 sporadic patients with hypodontia in China, as well as 196 healthy control individuals (without oligodontia or hypodontia) were screened. Congenital absence of teeth was confirmed by panoramic X-ray analysis.

[Functional analysis of novel mutations in PAX9 associated with familial oligodontia].

Objective: To gain new insights into the molecular pathogenesis of the 109(InsG) and 139(C--> T) mutations and their roles in familial oligodontia.

Methods: The region of PAX9 paired domain (PAX9PD) was amplified and the expression plasmids were constructed in pGEXlambda -1T by PCR-based cloning. PAX9PD proteins were prepared on the basis of GST instruction.

[The expression of TGF-beta1 mRNA in the maxillary sutures of puberty rhesus loaded with the class III intermaxillary orthopedic force].

Objective: The purpose of the study is to detect the expression of TGF-beta1 mRNA in the maxillary sutures of puberty rhesus during different periods of the loading of intermaxillary class III orthopedic force.

Methods: The animal model was established with 6 puberty female rhesus, which were randomly divided into experimental group (wearing class III twin-block magnet appliance, each 2 rhesus for 3 and 6 month respectively) and control group (not wearing any appliance, each 1 rhesus for 3 and 6 month respectively). Tissue sections were obtained perpendicular to the sutures.

[The expression of TGF-beta 1 mRNA in pubescent rhesus monkeys' condyle under Class III intermaxillary functional orthopedic force].

Objective: To investigate the expression of TGF-beta 1 mRNA in pubescent Rhesus monkeys' condylar under Class III intermaxillary functional orthopedic force for different lengths of time.

Methods: Six pubescent Rhesus monkey were divided into two test groups and a control group. Monkeys in the test groups were TMAIII while the control groups did not.