Vitamin B1 Involved in Dendrobium Taiseed Tosnobile Extract Mediates Protection Against Cancer-Induced Muscle Wasting by Suppressing IL-6 Pathogenicity and Enhancing Myoblast Fusion.

In this report, we showed that oral administration of Dendrobium Taiseed Tosnobile (DTT, also known as Taiwan Emperor No.1) allowed Lewis Lung Carcinoma (LLC) tumor-bearing mice to maintain body weight and grip strength in a dose-dependent manner. Histological analysis showed that treatment with DTT water extract significantly reduced muscle fiber damage by inducing muscle regeneration and improved the cross-sectional area of the rectus femoris, soleus, and gastrocnemius of LLC tumor-bearing C57BL/6 female mice. Further studies revealed that DTT water extract also reduced the expression of inflammatory cytokines such as IL-6 and TNF-α, both in vitro and in vivo. Other analyses showed that DTT water extract promoted the differentiation of C2C12 myoblasts with or without IL-6 by maintaining Myosin Heavy Chain (MyHC) levels. This suggests that DTT water extract acts against muscle wasting via multiple mechanisms. Interestingly, vitamin B1 was identified as an ingredient in DTT water extract through an HPLC analysis. Vitamin B1 was shown to ameliorate IL-6 but not TNF-α generation in active THP-1 cells and protected C2C12 myotubes against IL-6. Further studies showed that DTT and vitamin B1 promoted the multi-nucleus fusion step of C2C12 differentiation by inducing E-cadherin-β-catenin expression with or without IL-6 treatment. In summary, DTT water extract protects muscle cells under cancer conditions through direct and indirect mechanisms, with vitamin B1 being a key functional ingredient that reduces IL-6 generation and aids muscle cell fusion against IL-6 treatment.