Effects of cold-damp and hot-damp environment on VEGF and IL-1 expression in joint cartilage cells in adjuvant arthritis in rats

ObjectiveTo study the effects of environmental factors on the degree of injury and expression of vascular endothelial growth factor (VEGF) and interleukin-1 (IL-1) in cartilage cells of the joint in a rat model of adjuvant arthritis (AA).MethodsSD rats aged 10 months were randomly divided into 4 groups that varied by temperature and humidity housing conditions and induction of AA: a control group, a model group, a cold-damp group, and a hot-damp group. All groups except the control group were induced with AA. After 4 w, VEGF and IL-1 expression in cartilage cells of ankle joints of hind limbs were observed.ResultsMean area, optical density, and numbers of VEGF- and IL-1-positive cells in the model group, the cold-damp group, and the hot-damp group were significantly higher than that of the control group (all P<0.05). Optical density and positive cell numbers in the cold-damp group and the hot-damp group were significantly higher than that of the model group (all P<0.05). Optical density and positive cell numbers in the hot-damp group were significantly higher than that of the cold-damp group. Bone in the hot-damp and cold-damp groups was severely injured.ConclusionEnvironmental factors such as high humidity combined with either high or low temperature increase the severity of damage and expression of VEGF and IL-1 in cartilage cells of joints in rats induced with AA.