Tonifying Shen-Yin and-Yang Principles in Treating Osteoporosis: All Roads Lead to Rome

Tonifying Shen strategy works as an important alternative and complementary method that is widely used to treat osteoporosis in Traditional Chinese Medicine(TCM) based on the proper identification of Zheng. Shen deficiency Zheng is one of the main types of osteoporosis while Shen-Yin and-Yang deficiencies represent two basic principles/types of Shen deficiency. Currently, Tonifying Shen strategy, in particular, the Tonifying Shen-Yin and-Yang principles, has been demonstrated to exert osteoprotective effects. However, the mechanisms by which Tonifying Shen strategy and/or Tonifying Shen-Yin and-Yang principles function in treating osteoporosis are still not clearly understood. Here we first briefly explore current understanding of Tonifying Shen strategy, such as Tonifying Shen prescriptions, herbs, and effective components, in treating osteoporosis. Furthermore, the mechanism of Tonifying Shen-Yang principle in treating osteoporosis is reviewed from the clinic experience, animal, and mechanistic investigation. Moreover, the mechanisms by which Tonifying Shen-Yin principle in treating osteoporosis are established. Finally, we compare the similarity and difference between Tonifying Shen-Yang and-Yin principles in treating osteoporosis.Our findings indicate that both principles exert bone-protective effects in treating osteoporosis by simultaneously stimulating the differentiation of mesenchymal stem cells(MSCs) into osteoblast and the differentiation of hematopoietic stem cells(HSCs) into osteoclast. However,Tonifying Shen-Yin principle is in favor of increasing bone mineral density(BMD) while Tonifying Shen-Yang principle is in favor of osteoporosis-related syndromes. Our findings indicate that Tonifying Shen-Yin and-Yang principles not only share some similarity but also obtain some difference in treating osteoporosis.