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Objective To observe the biological behavior of chondrocytes in chitosan based hydrogel in vitro and to evaluate the possibility of chitosan and glycerophosphate mixed gel using as injectable scaffolds in tissue engineering.Methods A novel injectable thermosetting gel was made of chitosan and glycerophosphate mixture.Chondrocytes isolated by enzymic digestion from the articular cartilage of the young rabbits aged 3-4 weeks were cultured in monolayer system.After primary culture and subculturing,the cells were seeded in chitosan based gel in concentration of 5?10~7/ml in vitro.Characteristics of chondrocytes during 4-week culture were observed with invert microscope.MTT was used to detect the seed growth after one-week culture.In 4th week,after haematoxylin eosine and toluidine blue staining,the artifical cartilage was performed type Ⅱ collagen immunohistochemistry and observed by scanning electron microscope.Results Chondrocytes retained their round morphology,multiplied,and produced matrix in chitosan and glycerophosphate mixture gels.The results of immunohistochemistry were strongly positive.Conclusion That most chondrocytes appeared to occupy large areas of rough chitosan based gels,guarantees a suitable environment where chondrocytes secrete matrix macromolecules and preserve their round morphology in vitro.Chitosan and glycerophosphate mixture gel may be a vehicle for injectable tissue-engineered cartilage.
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The brainstem ischemic injuries were produced by the occlusion of the basilar artery for 6 h in dogs. Gypenoside (150 mg ?kg-1)were intradudinally given at 3 h before the occlusion. We discovered that gypenoside alleviated the ischemic neuronal damage (histopathologically evaluated by the light and electronic microscope), ameliorated the abnormal changes of brainstem auditory evoked potentials (BAEP) (F
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Objective To observe the dynamic changes of the content and the activity of phospholipase A 2(PLA 2) after ischemia in canine brainstem and to explore the neuroprotection of taurin and the activation of PLA 2. Methods The ischemic brainstem models were established with dog.The content of taurin and the activity of PLA 2 were determined after different durations of ischemia in the brainstem with Gold series high performance aminoacid analyzer and trace acid titration respectively. Meanwhile,the pathological changes of neurons were observed with microscope. Results Compared with those of the pseudo operation group,the content of taurin and the activity of PLA 2 in the brainstem increased significantly 30 min after ischemia in the brainstem ( P