Lycium barbarum polysaccharide protects diabetic peripheral neuropathy by enhancing autophagy via mTOR/p70S6K inhibition in Streptozotocin-induced diabetic rats.

Lycium barbarum polysaccharide (LBP), the major active component of Lycium barbarum, has been found to be effective in the management of some diabetic complications. We evaluated the protective effect of LBP in diabetic peripheral neuropathy (DPN) and explored the possible mechanisms. We found that LBP mildly decreased blood glucose levels and partially rescued allodynia and hyperalgesia in the diabetes mellitus (DM) rats. For the electrophysiological function of the sciatic nerve, the decrease in sensory nerve conduction velocity (SNCV) and sensory nerve action potential (SNAP) amplitudes in DM rats were partially rescued. Moreover, DM-induced structural damage to the nerve fiber myelination showed great improvement by 12 weeks of LBP treatment. The decreased expression of the myelin-related proteins, myelin protein zero (P0) and myelin basic protein (MBP), in the DM sciatic nerve was also markedly rescued after 12 weeks of LBP treatment. Furthermore, the possible role of mammalian target of rapamycin (mTOR)-mediated autophagy during these protective processes was examined. The expression of microtubule-associated protein light chain 3-II(LC3-II) and Beclin1 in the sciatic nerve was significantly decreased while the expression of P62 increased in DM rats, demonstrating an decreased activation of autophagy. As expected, the LC3-II and Beclin1 protein levels were markedly increased, and P62 was markedly decreased after LBP treatment. The expression of mTOR, p-mTOR, p70 ribosomal protein S6 kinase (p70S6K) and p-p70S6K in the DM group were markedly increased, while all of these proteins decreased in LBP group. These results demonstrate that LBP exerts protective effects on DPN, which is likely to be mediated through the induction of autophagy by inhibiting the activation of the mTOR/p70S6K pathways.

Nitric oxide participates in cold-inhibited Camellia sinensis pollen germination and tube growth partly via cGMP in vitro.

Nitric oxide (NO) plays essential roles in many biotic and abiotic stresses in plant development procedures, including pollen tube growth. Here, effects of NO on cold stress inhibited pollen germination and tube growth in Camellia sinensis were investigated in vitro. The NO production, NO synthase (NOS)-like activity, cGMP content and proline (Pro) accumulation upon treatment with NO scavenger cPTIO, NOS inhibitor L-NNA, NO donor DEA NONOate, guanylate cyclase (GC) inhibitor ODQ or phosphodiesterase (PDE) inhibitor Viagra at 25°C (control) or 4°C were analyzed. Exposure to 4°C for 2 h reduced pollen germination and tube growth along with increase of NOS-like activity, NO production and cGMP content in pollen tubes. DEA NONOate treatment inhibited pollen germination and tube growth in a dose-dependent manner under control and reinforced the inhibition under cold stress, during which NO production and cGMP content promoted in pollen tubes. L-NNA and cPTIO markedly reduced the generation of NO induced by cold or NO donor along with partly reverse of cold- or NO donor-inhibited pollen germination and tube growth. Furthermore, ODQ reduced the cGMP content under cold stress and NO donor treatment in pollen tubes. Meanwhile, ODQ disrupted the reinforcement of NO donor on the inhibition of pollen germination and tube growth under cold condition. Additionally, Pro accumulation of pollen tubes was reduced by ODQ compared with that receiving NO donor under cold or control condition. Effects of cPTIO and L-NNA in improving cold-treated pollen germination and pollen tube growth could be lowered by Viagra. Moreover, the inhibitory effects of cPTIO and L-NNA on Pro accumulation were partly reversed by Viagra. These data suggest that NO production from NOS-like enzyme reaction decreased the cold-responsive pollen germination, inhibited tube growth and reduced Pro accumulation, partly via cGMP signaling pathway in C. sinensis.

Characterization of the expression profiles of calpastatin (CAST) gene in chicken.

The calpain system, a Ca(2+)-activated protease family, plays an important role in postmortem tenderization of skeletal muscle due to its involvement in the degradation of important myofibrillar and associated proteins, as well as in cytoskeletal remodeling and regulation of muscle growth. In this study, we quantified the expression of calpastatin (CAST) in two Chinese chicken breeds (mountainous black-bone chicken breed (MB) and a commercial meat type chicken breed (S01)), to discern the tissue and age-related specific expression pattern and its potential role on muscle tissue metabolism. Real-time quantitative PCR (RT-qPCR) assay was developed for accurate measurement of CAST mRNA levels in various tissues from chicken with different ages (0, 2, 4, 6, 8, 10, and 12 week). CAST mRNA was detected in collected organs. The heart and leg muscle tissues had the highest expression of CAST than other tissues from the same chicken (P < 0.01). Age-related expression pattern of CAST gene was evident in breast muscle, liver, and brain tissues (P < 0.05), but not in heart and leg muscle tissues (P > 0.05). Overall, the CAST mRNA level exhibited a "rise-decline-rise-decline" developmental change in breast muscle and liver, with the highest expression at 2 weeks and the lowest expression at 8 weeks. The S01 chicken had significantly higher expression of CAST in breast muscle and heart than the MB chicken (P < 0.05) at 10 weeks. Our results suggested the CAST expression may be related to muscle fiber development.