CCN2 and diabetic kidney disease: Ma et al. applied tripterygium glycosides combined with irbesartan to explore the effect on urinary podocyte excretion in DKD patients, and the results indicated that the combination of the tripterygium glycosides and irbesartan was effective for preventing podocyte injury in DKD patients, which might be achieved by down-regulating the expressions of connective tissue growth factor (CTGF), osteopontin and TGF-β(Ma et al., 2013).