SMAD2 and liver dysplastic nodule: At the same time, the expression levels of fibrosis-related proteins such as TGF-β1, p-Smad2, and p-Smad3 in the kidney decreased significantly, suggesting that salidrosdie slows down the pathological changes of kidney tissue and improves renal sclerosis and fibrosis in DN rats by inhibiting the TGF-β1/Smad2/3 pathway (Qi et al., 2021).