ABSTRACT
Periodontal tissue has a unique structure in that the human periodontal ligament (hPDL) lies between the hard tissues of cementum and alveolar bone. Although the role of cytokines in hPDL function is not clearly understood, we investigated the effect of mechanical stress as hydrostatic pressure (HP) on cytokine expression in hPDL cells.The hPDL cells were obtained from a healthy maxillary third molar. After the 3rd to 4th passage, the cells were exposed to HP ranging from 1 MPa to 6 MPa as previously described. The expression of cytokine mRNA was determined by RT-PCR and cytokines in the culture supernatants were assessed by enzyme-linked immunosorbent assay (ELISA).The exposure to 6 MPa of HP caused no morphological changes of hPDL cells, and did not affect cellular viability. No expression of IL-1β, IL-6, IL-8, TNF-α, RANK, RANKL or OPG mRNA was observed in the control cells under atmospheric pressure, whereas in hPDL cells treated with HP, enhancement of IL-6, IL-8, RANKL and OPG mRNA expression was observed between 10 and 60 minutes after the exposure to HP. After the exposure to HP, the production of IL-6 and TNF-α were induced significantly in hPDL cells, but IL-1β and IL-8 were not produced.These results suggest that hPDL cells may play a role in the production of cytokines in response to mechanical stress <i>in vivo</i>.
ABSTRACT
Seven patients with hemiplegia due to cerebral apoplexy and 5 subjects without any sign of cardiovascular abnormalities (as the contol cases) were used in this study. Systemic blood pressure by sphygmomanometer, digital blood pressure and digital blood flow by digital plethysmograph were recorded and the peripheral vascular resistance was calculated from the values. The extensibility of arterial wall was calculated from transmission time of the pulse wave and length of the vessel. The effect of bathing therapy in hot spring water (sodium sulphate spring; bathing temperature ranging from 41-43C; bathing duration ad libitum) on the peripheral vascular hemodynamics was examined.<br>1. Effects of single bathing<br>In patients with hemiplegia, systolic blood pressure decreased 40mm Hg in the paralyzed, but slightly in the unparalyzed side, and also the decrease of digital blood pressure was greater in the former than in the latter. Digital blood flow increased and the peripheral vascular resistance decreased in both sides, and the rate of change was much greater in the paralyzed than in the unparalyzed side, respectively.<br>In the control cases, the changes were fairly comparable to those in the unparalyzed side of the patients except the extensibility of the arterial wall which was manifest in both sides of the patients but only scarce in the control subjects.<br>2. Effects of repeated bathing<br>In patients with hemiplegia who had taken the bathing therapy for 30-90 days, the digital blood flow increased and the paripheral vascular resistance decreased but without noticeable differences between the paralyzed and the unparalyzed side, and the size of the increase or the decrease was almost equal to that in the control subjects. Increase in the extensibility of arterial wall was found more in the patients than in the controls. In general the effects of repeated bathing were less distinguished than those of single bathing.