No abstract

In order to establish a method of obtaining rat gingival mitochondria (Mt), Mt fractions were prepared in various combinations of homogenizing time with collagenase concentration. Rat gingival tissues were excised, minced, treated with collagenase, homogenized, and subjected to differential centrifugation rates. Both the respiratory control ratio (RCR) and adenosine diphosphate/oxygen (ADP/O) ratio of the Mt fraction prepared in a combination of 40, 50, or 60 sec homogenization with collagenase in a concentration range of 0.115%–0.130% (w/v) were measured. The values for the RCR and ADP/O ratio of the Mt fraction obtained in an optimal condition was 1.80 ± 0.05 and 1.65 ± 0.03, respectively. These results suggest that Mt of fairly high quality can be obtained through this refined combination of the homogenizing time and collagenase concentration.

AimOral care is associated with improved quality of life and changing cognitive performance in daily life. The association of trigeminal nerve‐stimulatory oral care methods, such as tooth brushing and intra‐oral cold stimuli, with cerebral activation has been studied. This study aimed to elucidate the effects of intra‐oral gingival massage on the cerebral prefrontal cortex (PFC) region activation and the changes in cognitive performance.MethodsA total of 18 men participated in this study. Near‐infrared spectroscopy was used to acquire data on the cerebral hemoglobin concentrations. Cognitive function was determined using the Stroop cognitive test performed with and without intra‐oral gingival massage stimulus.ResultsParticipants who performed intra‐oral gingival massage showed significantly increased blood flow in the cerebral PFC region, including the left dorsolateral PFC (DL‐PFC) region, compared with those who mimicked the movements of the gingival massage (control group) (p = 0.0104 by Wilcoxon signed rank method). Furthermore, gingival massage showed a significant association with increased cognitive performance (p < 0.0001 by Wilcoxon signed rank method) that coincided with the enhanced left DL‐PFC region activation (p = 0.039 by Fisher's exact probability test).ConclusionIntra‐oral gingival massage activated the cerebral PFC regions correlating with enhanced cognitive performance, suggesting that gingival massage may help improve cognitive performance.