Objective To explore the relationship among the expression level of MMP?13, AGG and Col?II in the chon?drocytes caused by nutritional deficiencies in rabbits. Methods 30 New Zealand white rabbits were randomly divided into autolo?gous chondrocyte transplantation group (control group, n=10), nutrition block group (surgery group, n=10), and peripheral nutrition block group (sham surgery group, n=10). 4 weeks after treatment, the rabbits were sacrificed for undergoing the observations on general and histological level;real?time PCR assay was employed for testing the expression level of MMP?13, AGG and Col?II;cel?lular apoptosis percentage was observed through TUNEL stain. The relationship among the apoptosis level, cartilage cells histologi?cal Mankin score as well as the expression level of MMP?13, AGG and Col?II were analyzed. Results Based on the Mankin score, there was a statistic difference between surgery group and control group. On the other side, there were no statistic differenc?es between sham surgery group and control group. 4 weeks after treatment, surgery group presented a higher apoptotic percentage compared with control group;this value between sham surgery group and control showed no significant differences. There was an increased mRNA expression level of MMP?13 and a decreased mRNA expression level of AGG and Col?II in surgery group com?pared with control group;no statistic differences of all these values was found between sham surgery group and control group. His?tological Mankin score and apoptotic percentage presented positive correlation (r=0.922, P<0.001), the regression equation:Y=-0.548+0.404X, R2=0.844 (F=157.735, P<0.001); the mRNA expression level of MMP?13 and apoptotic percentage presented positive correlation (r=0.942, P<0.001), the regression equation:Y=0.951+0.116X, R2=0.883 (F=219.054, P<0.001). There was a nega?tive correlation between the mRNA expression level of MMP?13 and the mRNA expression level of AGG as well as Col?II (r=-0.956,-0.945, P<0.001). Conclusion Damage of cartilage cells causes the up?regulation of the MMP?13 expression which could ex?acerbate the degeneration of cells. It could induce the down?regulation of AGG and Col?II mRNA expression, which will cause the extracellular matrix synthesis disorder.

Background The mental health status of prison officers is crucial to the efficiency, security, and stability of a prison, and it is essential to pay attention to the factors that influence their mental health. Objective To understand the mental health status of prison officers, and analyze how nature exposure affects their mental health problems and a potential mediating role of mental fatigue. Methods A cross-sectional survey was carried out from May to June 2022 among 1392 prison officers from eight prisons in a province, and a total of 1284 valid questionnaires were recovered. The Nature Exposure Scale, Mental Fatigue Scale, and Depression-Anxiety-Stress Scale were used to assess nature exposure, mental fatigue, and mental health indicators among prison officers, and to explore the effect of nature exposure on mental health problems and a potential mediating role of mental fatigue. Results The recruited prison officers showed high levels of depression, anxiety, and stress. The prevalence rates of depression, anxiety, and stress were 59.11% (759/1284), 60.67% (779/1284),and 43.93% (564/1284), respectively. The results of correlation analysis revealed that nature exposure was negatively related with mental fatigue and mental health indicators (depression, anxiety, and stress) (r_s=−0.242, −0.308, −0.235, −0.254, P<0.01), while mental fatigue was positively correlated with mental health indicators (depression, anxiety, and stress) (r_s=0.546, 0.533, 0.536, P<0.01). The PROCESS macro results showed that the level of nature exposure among prison officers negatively associated with depression, anxiety, and stress (β=−0.180, −0.104, −0.123), and mental fatigue played a mediating role, with indirect effects of −0.200, −0.192, and −0.199, respectively. Conclusion The levels of depression, anxiety, and stress of prison officers are higher than those of other occupations. Nature exposure negatively associates with depression, anxiety, and stress, that is, it may directly alleviate the mental health problems of prison officers; and it may also alleviate mental health problems by relieving mental fatigue.