Chitosan hydrogel encapsulated with LL-37 peptide promotes deep tissue injury healing in a mouse model.

BACKGROUND: LL-37 peptide is a member of the human cathelicidin family, and has been shown to promote the healing of pressure ulcers. However, the low stability of this peptide within the wound environment limits its clinical use. Chitosan (CS) hydrogel is commonly used as a base material for wound dressing material. METHODS: CS hydrogel (2.5% w/v) was encapsulated with LL-37. Cytotoxicity of the product was examined in cultured NIH3T3 fibroblasts. Effects on immune response was examined by measuring tumor necrosis factor-α (TNF-α) release from RAW 264.7 macrophages upon exposure to lipopolysaccharides. Antibacterial activity was assessed using Staphylococcus aureus. Potential effect on pressure ulcers was examined using a mouse model. Briefly, adult male C57BL/6 mice were subjected to skin pressure using magnets under a 12/12 h schedule for 21 days. Mice were randomized to receive naked LL-37 (20 µg), chitosan gel containing 20-µg LL-37 (LL-37/CS hydrogel) or hydrogel alone under the ulcer bed (n = 6). A group of mice receiving no intervention was also included as a control. RESULTS: LL-37/CS hydrogel did not affect NIH3T3 cell viability. At a concentration of 1-5 µg/ml, LL-37/CS inhibited TNF-α release from macrophage. At 5 µg/ml, LL-37/CS inhibited the growth of Staphylococcus aureus. The area of the pressure ulcers was significantly lower in mice receiving LL-37/CS hydrogel in comparison to all other 3 groups on days 11 (84.24% ± 0.25%), 13 (56.22% ± 3.91%) and 15 (48.12% ± 0.28%). Histological examination on days 15 and 21 showed increased epithelial thickness and density of newly-formed capillary with naked LL-37 and more so with LL-37/CS. The expression of key macromolecules in the process of angiogenesis (i.e., hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor-A (VEGF-A)) in wound tissue was increased at both the mRNA and protein levels. CONCLUSION: Chitosan hydrogel encapsulated with LL-37 is biocompatible and could promote the healing of pressure ulcers.

Contributions of endothelin in the process of the noise-induced injury of inner ear / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To study the pathological alteration of the cochlear microcirculation and the role of endothelin (ET) in the process of the noise-induced injury of inner ear.</p><p><b>METHODS</b>Thirty rats were randomly divided into five groups: control group and 1, 4, 8, 15 d noise exposure groups (115 dB, white noise, 8 h daily). The cilium of hair cell was observed by scanning electron microscope, the cochlear microcirculation was determined by stretched preparation of the stria vascularis. The level of ET in plasma was measured through radio-immunity. The distribution of ET-1, ETA, ETB, in cochlea were detected through immunohistochemistry staining.</p><p><b>RESULTS</b>In the 4, 8, 15 d group, severe ischemia appeared on the capillary of stria vascularis and the cilium of hair cell displayed significantly disorder. The level of ET in plasma rose temporarily in the 4 d group. ET-1 activity distributed widely in the rat cochlea, there was no significant difference between the control group and the noise exposure groups. ETA expressed in the plasma of the intermediate cells and the capillary walls in the stria vascularis. The control group and the 1 d group showed weak positive staining, while the 4, 8, 15 d groups showed strong positive. The ETB, activity distributed on the endothelial cells of the capillary of stria vascularis and the alteration of the staining intensity was similar to the manifestation of ETA.</p><p><b>CONCLUSIONS</b>Severe disturbance of the cochlear circulation occurred during the course of the noise injury to the inner ear. At the same time, the activity of the ET system of the cochlea stepped up significantly. It coincided with the ischemia of the stria vascularis. These findings suggest that ET may play an important role in the process of the cochlear microcirculation disorder caused by noise.</p>

Observation of Curative Effect of Matrine Injection on Infant Cytomegalovirus Hepatitis / 实用儿科临床杂志

0.05).2.There were significant differences in the levels of TNF-? after treated for 4 weeks(P0.05).4.There were no significances between the 2 groups before and after treated 6 weeks in the change of liver.Conclusions Matrine injection can inhibit HCMV DNA replication.It can also control the expression of TNF-? and regulate the function of the immune system.There fore matrine injection has an antivirus efficacy in HCMV infection.