The effects of chronic hypoxia on the endocrine-related parameters in elderly rats with type 2 diabetes mellitus

This study aimed to investigate the effects of chronic hypoxia on the endocrine-related parameters in elderly rats with type 2 diabetes mellitus.

Sixty, 55-week-old, female SD rats were studied, among which 20 were randomly divided into a blank control group (the BCG), and 40 were intraperitoneally injected with low-dose streptozotocin (STZ) for modeling and divided into a model control group (the MCG, n=20) and a hypoxic group (the HG, n=20). The BCG and the MCG were fed routinely under normoxia, while the HG was fed in the hypoxic environment of an OxyCycler Model A84XO hypoxic chamber. After 12 weeks of intervention, the body weights, the fasting blood glucose (FBG) levels, the fasting insulin (FINS) levels, the blood lipid metabolism levels, the bone densities, the fresh weights of the femurs, the biomechanical properties of the femurs, the inflammatory factor levels, the H&E staining of the liver tissue, and the oil red O staining were compared.

The increases in weight gain and the FBG and FINS levels in the HG were lower than the corresponding levels in the MCG and were higher than the levels in the BCG (P<0.05). The TC, TG, and LDL-C levels in the HG were lower than they were in the MCG and higher than they were in the BCG (P<0.05). The bone density and fresh weight of the femurs at 12 weeks after the intervention in the HG were higher than they were in the MCG and lower than they were in the BCG (P<0.05). The maximum stress, maximum load, fracture load, and elastic modulus in the HG were higher than they were in the MCG and lower than they were in the BCG (P<0.05). The TNF-α, IL-6, PAI-1, and CRP levels in the HG were lower than they were in the MCG and higher than they were in the BCG (P<0.05).

Chronic hypoxia can improve the endocrine parameters and insulin resistance, improve the insulin sensitivity and the femoral biomechanics, reduce the inflammatory factors levels, and improve the glucose and lipid metabolism levels and liver function in elderly rats with type 2 diabetes.