Effects of a simulated plateau environment on fracture healing in rats / 中华创伤骨科杂志

Objective:To study the effects of a simulated plateau environment on fracture healing in rats.Methods:A rat model of mid-femoral fracture was established by hacksaw truncation and intramedullary fixation with Kirschner wires in 60 male Wistar rats which were divide into 2 groups ( n=30) by the random number table method. The rats in the control group were raised in the animal experiment center of The 940 Hospital of Joint Logistic Support Force of Chinese PLA at an altitude of 1,400 m, while the rats in the plateau group were placed in an animal experimental cabin in a simulated plateau environment at a simulated altitude of 5,000 m. The body weight was weighed once a week and X-ray films were taken every 2 weeks. Blood samples were collected after 4 weeks for detection of biochemical indicators of bone metabolism. After 8 weeks, the femurs of the surgical side were taken for bone biomechanical detection and the bone mineral density of the healthy side was detected. After 4 and 8 weeks, the femurs of the surgical side were taken for in vitro Micro-CT scanning and angiography detection. After 1, 2, 4 and 8 weeks, the femurs of the surgical side were taken for bone histopathologic detection. Results:During the entire experiment, no rats in the control group died while the mortality rate of the rats in the plateau group was as high as 26.7% (8/30). In the plateau group, some organs were pathologically damaged in the rats, fracture union was delayed, and the callus differentiated and matured slowly with the chondrocytes still dominant at the 8th week. The bone mineral density and the maximum load of the femur in the plateau group were significantly lower than those in the control group ( P< 0.05). Angiography showed that the rats in the plateau group had microvascular proliferation which did not penetrate the fracture end at the 8th week. The bone formation indexes like osteocalcin, procollagen type Ⅰ N-terminal propeptide (PⅠNP), and osteoprotegerin of the rats in the plateau group were significantly lower than those in the control group at the 4th week ( P<0.05). The bone resorption indexes like tartrate resistant acid phosphatase 5b (TRACP-5b) and receptor activator for nuclear factor-κB ligand (RANKL) in the plateau group were significantly higher than those in the control group ( P<0.05). Conclusion:A simulated plateau environment at an altitude of 5,000 m may lead to delayed fracture healing in rats.

Progress of research on the relationship between Parkinson's disease and osteoporosis in hypoxic environments / 中华老年医学杂志

Parkinson's disease is a progressive neurodegenerative disorder often seen in the elderly and seriously affects patients' quality of life.Osteoporosis is also a common systemic metabolic bone disease in the elderly characterized by a predisposition to fractures.Studies have shown that Parkinson's disease is highly correlated with osteoporosis, and patients with Parkinson's disease are at high risk for osteoporosis.Hypoxic environments may aggravate the disease and its complications in patients with Parkinson's disease, and the possible mechanisms may involve inhibition of growth and differentiation of osteoblasts, promotion of the formation of osteoclasts, and thus increased risk of osteoporosis under hypoxic conditions.Recent studies have reported that hypoxia, low air pressure, strong sunlight exposure and diets are associated with Parkinson's disease and osteoporosis at high altitudes.This paper reviews research progress on the relationship between Parkinson's disease and osteoporosis in hypoxic environments.

Advances in the study of gut pharmacomicrobiomics / 药学学报

The intestinal flora is a diverse microbial community living in the digestive tract of humans and animals. This microbial community can modify drugs in unpredictable ways, leading to changes in the pharmacokinetics of drugs in vivo and affecting their clinical efficacy. Here we review drug metabolism mediated by intestinal flora from three aspects: prodrug activation, drug inactivation, and toxicity. The effect of the stable hypoxic environment on the composition and quantity of intestinal flora and the effect on drug metabolism are discussed. Understanding the influence of intestinal flora on drug metabolism is not only conducive to individualized medication, but also conducive to rational drug design, allowing us to predict and understand individual drug response and regulate the intestinal microbiome to improve drug efficacy, thus promoting personalized medicine.

Effects of hypoxic exposure and endurance exercise training on the oxidative potentials of soleus muscle fibers and motoneurons in the rat / 体力科学

Thirty (n=30) seven week old male Sprague-Dawley rats were divided into six groups of five rats (n=5) in each group. The groups were designated Sc=sea level controls; St=sea level trained; Fc=hypoxic exposed (16% O<SUB>2</SUB>) controls; Ft =hypoxic exposed (16% O<SUB>2</SUB>) trained; Pc=intermittent hypoxic exposed (18%, 16%, 14%, 16%, 18% O<SUB>2</SUB> for two days each) controls; and Pt=intermittent hypoxic exercise trained. Exercise training consisted of 45min/day running on a rat treadwheel for 24 consecutive days. Fiber type distribution, succinate dehydrogenase (SDH) activity and glycogen content of the soleus muscle and the oxidative enzyme activity of the motoneurons of the soleus were measured in each group after the 24 days of hypoxic exposure and exercise training. In comparison to each training group's control the glycogen concentration of the soleus muscle was increased (P<0.05) regardless of hypoxic exposure. Only the intermittently hypoxic exercise trained group (Pt) demonstrated a fiber type shift of slow-twitch oxidative to fast-twitch oxidative glycolytic fibers. Neither hypoxia or exercise training altered the oxidative enzyme capacity of the soleus motoneurons.

Effects of exposure to simulated high altitude on red-cell 2,3-DPG, salivary cortisol and plasma testosterone levels during training in female swimmers / 体力科学

Thirteen female swimmers (ranging in age from 15 to 18 years) were selected as subjects and divided into two groups; group A (subjects of experiment) consisted of six subjects in whom low pressure was loaded and group B (subjects of control) consisted of seven in whom low pressure was not given.<BR>During training, circuit weight training was performed in a low pressure environment and it was combined with conventional swimming training. We studied the effect of these types of training on their red-cell 2, 3-diphosphoglycerate, salivary cortisol, and plasma testosterone.<BR>(1) The 2, 3-DPG level showed a greater increase after loading exercise than at the time of resting in both groups A and B. The increase was highly significant in group A. Additionally, 10 days after the removal of the loading, hemoglobin and hematocrit levels were significantly decreased in groups A and B, and a significant increase in 2, 3-DPG was observed in group A.<BR>(2) Only after loading low pressure was the cortisol level higher in group A than in group B. However, there was no significant difference between the two groups in the amount of exercise loading when heart rate was used as the index.<BR>(3) Testosterone tended to show a greater increase after exercise loading than on the first day of the experiment. However, neither an effect of exposure to low pressure on testosterone nor a significant difference between the two groups was observed.<BR>According to the results, in swimming, an endurance contest, physical changes during training are almost the same in group A and B, but it is considered that a concurrent severe hypoxic condition as a result of low pressure loading brings about homeostasis in the living body and the homeostasis leads to an attempt to increase oxygen uptake by the tissues, yeilding increased staying power.