RESUMO

Abstract This study investigated the inhibitory effect of Dendrobium officinale polysaccharide (DOPA) on human gastric cancer cell SGC-7901 xenografts in nude mice. The nude mice with SGC-7901 xenografts were randomly divided into model, 5-fluorouracil (5-Fu), low-dose DOPA, middle-dose DOPA and high-dose DOPA group. The later four groups were intragastrically administrated with 100, 200 and 400 mg·kg-1·day-1 DOPA, 400 mg·kg-1·day-1 5-Fu and normal saline, respectively. After treatment for 20 days, the tumor inhibition rate of in high-dose DOPA group was basically equivalent to 5-Fu group. Compared with 5-Fu, DOPA had no obvious toxic side effect on spleen or thymus indexes, routine blood indexes or liver and kidney functions of nude mice. Compared with model group, the serum tumor necrosis factor-α and interleukin-2 levels in middle- and high-dose DOPA group were significantly increased (P < 0.05), Bax protein expression was significantly increased (P < 0.05), and Bcl-2 protein expression was significantly decreased (P < 0.05). DOPA can inhibit the growth of SGC-7901 cell xenografts in nude mice. The mechanism may be related to its increase of serum TNF-α and IL-2 levels, up-regulation of Bax protein expression and down-regulation of Bcl-2 protein expression.

Assuntos

Humanos , Animais , Camundongos , Neoplasias Gástricas , Ensaios Antitumorais Modelo de Xenoenxerto , Plantas Medicinais , Polissacarídeos , Neoplasias Gástricas/terapia , Dendrobium , Xenoenxertos , Camundongos Nus

RESUMO

Wolbachia naturally infects a wide variety of arthropods, where it plays important roles in host reproduction. It was previously reported that Wolbachia did not infect silkworm. By means of PCR and sequencing we found in this study that Wolbachia is indeed present in silkworm. Phylogenetic analysis indicates that Wolbachia infection in silkworm may have occurred via transfer from parasitic wasps. Furthermore, Southern blotting results suggest a lateral transfer of the wsp gene into the genomes of some wild silkworms. By antibiotic treatments, we found that tetracycline and ciprofloxacin can eliminate Wolbachia in the silkworm and Wolbachia is important to ovary development of silkworm. These results provide clues towards a more comprehensive understanding of the interaction between Wolbachia and silkworm and possibly other lepidopteran insects.