BACKGROUND:Pulsed electromagnetic fields,as an important physical therapy,are exactly effective in the treatment of osteoarthritis,but the mechanism has not been fully clarified. OBJECTIVE:To observe the effect of pulsed electromagnetic field on the degeneration of knee joint cartilage in aged rats. METHODS:Eight 6-month-old Sprague-Dawley rats were selected as the young group and were subjected to normal diet with no treatment.Sixteen 22-month-old Sprague-Dawley rats were randomly divided into old group(n=8)and pulsed electromagnetic field group(n=8).The rats in the pulsed electromagnetic field group were subjected to a pulsed electromagnetic field intervention,once a day,5 days per week for continuous 8 weeks.The rats in the old group were given no treatment.All rats were anesthetized and executed after 8 weeks for the detection of relevant indexes. RESULTS AND CONCLUSION:Compared with the young group,serum type Ⅱ collagen C-terminal peptide level was increased in the old group(P<0.05);compared with the old group,serum type Ⅱ collagen C-terminal peptide level was decreased in the pulsed electromagnetic field group(P<0.05).Micro-CT showed that the bone volume fraction,bone mineral density,and number of bone trabeculae decreased(P<0.05)and the trabecular separation increased(P<0.05)in the tibia of rats in the aged group compared with the young group;and the bone volume fraction,bone density,and number of trabeculae increased(P<0.05)and the trabecular separation decreased(P<0.05)in the tibia of rats in the pulsed electromagnetic field group compared with the aged group.The tibial plateau Safranin O-fast green staining showed that the articular cartilage structure of rats in the aged group was disorganized,and the number of chondrocytes was obviously reduced,and the tidal line could not be distinguished.The above results were improved in the pulsed electromagnetic field group.RT-qPCR and western blot assay showed that the mRNA and protein expression levels of matrix metalloproteinase 1,matrix metalloproteinase 13,P53 and P21 in the articular cartilage and subchondral bone of rats were elevated in the aged group compared with the young group(P<0.05)and decreased in the pulsed electromagnetic field group compared with the old group(P<0.05).To conclude,pulsed electromagnetic fields may improve osteoarthritis in aged rats by inhibiting chondrocyte senescence,alleviating articular cartilage degradation and inhibiting subchondral bone osteoporosis through suppressing the expression of P53/P21.

With the rapid progress of industrialization and commercialization, the sales and population intake of ultra-processed foods (UPFs) are constantly increasing globally. High UPFs intake is associated with various health issues. This article provided a brief overview of various health outcomes and explored the possible causes for the health impacts of UPFs consumption from the perspectives of processing and production. The review found that high UPFs intake increased the risks of adult overweight/ obesity, type 2 diabetes, cancer mortality, and anxiety disorders; maternal preeclampsia, gestational hypertension, and gestational diabetes; childhood and adolescent overweight/ obesity. High UPFs intake also affected embryonic development and offspring language development. The possible explanations for the negative health outcomes associated with UPFs were as follows. The convenience and increased accessibility of UPFs affect the dietary structure of the population. The combined exposure to refined carbohydrates and fats added to UPFs increases the desire and motivation for more energy intake. The complex processing process leads to the loss of dietary fibers and micronutrients, affecting human satiety, digestion rate, chewing duration, and producing toxic compounds such as furan, heterocyclic amines, polycyclic aromatic hydrocarbons, and acrolein. The introduction of more types and higher doses of food additives and the migration of exogenous pollutants from packaging materials to food pose potential health and safety risks. At present, there is little research on the relationship between UPFs and human health in China. Based on the known health risks of UPFs, more in-depth research is needed in order to better understand the relationship between UPFs and human health.