[Repair effect of bFGF combined with bone marrow mesenchymal stem cells on spinal cord injury in rats]

OBJECTIVE

To observe the repair effect of bone marrow mesenchymal stem cells (BMSCs) combined with basic fibroblast growth factor (bFGF) on spinal cord injury in rats and explore its mechanism.

METHODS

SD rat BMSCs were obtained by serum culture technique. Eighty healthy 6-week-old male SD rats(weight about 240 g) were randomly divided into 4 groups with 20 each. The sham operation group underwent simple laminectomy without damaging spinal cord and was kept in the same condition as the other 3 groups. The other 3 groups underwent left T9 spinal cord hemisection to establish spinal cord injury model. After 9 days of modeling the local transplantation was performed. The Control group was implanted with gelatin sponge containing normal saline. The BMSCs transplantation group was implanted with gelatin sponge containing BMSCs. The bFGF+BMSCs transplantation group was implanted with gelatin sponge containing bFGF+BMSCs. After 4 and 8 weeks, the expression of NF-200 and GFAP in injured spinal cord tissue was analyzed by Western blotting and the recovery of hind limb function was evaluated by Basso Beattie Bresnahan(BBB) motor function score scale.

RESULTS

The BBB scores of BMSCs transplantation group and bFGF+BMSCs transplantation group were better than control group at 4 and 8 weeks after operation (P<0.05) and there was significant difference between bFGF+BMSCs transplantation group and BMSCs transplantation group (P<0.05). After 4 and 8 weeks postoperatively, NF-200 expression was minimal in control group and only a small amount was expressed in BMSCs transplantation group while in bFGF+BMSCs transplantation group NF-200 was highly expressed(P<0.05). GFAP expression was high in control group, middle in BMSCs transplantation group and low in bFGF BMSCs transplantation group(P<0.05). There was significant difference between bFGF+BMSCs transplantation group, BMSCs transplantation group and control group(P<0.05).

CONCLUSIONS

The combined transplantation of BMSCs and bFGF can repair the spinal cord injury in rats. The mechanism may be related to the decrease of GFAP expression and the increase of NF-200 expression.

Inhibition of STAT3 by RNA interference suppresses angiogenesis in colorectal carcinoma

In order to investigate signal transduction and activation of transcription 3 (STAT3) signaling on angiogenesis in colorectal carcinoma (CRC) after inhibiting STAT3 expression, we constructed the HT-29-shSTAT3 cell line by lentivirus-mediated RNAi. Cell growth was assessed with MTT and the cell cycle distribution by flow cytometry. CRC nude mouse models were established and tumor growth was monitored periodically. On day 30, all mice were killed and tumor tissues were removed. Microvessel density (MVD) was determined according to CD34-positive staining. The expression of vascular endothelial growth factor A (VEGFA), matrix metalloproteinase-2 (MMP2) and basic fibroblast growth factor (FGF2) was monitored by quantitative real-time PCR and Western blot analysis. Knockdown of STAT3 expression significantly inhibited cell growth in HT-29 cells, with a significantly higher proportion of cells at G0/G1 (P < 0.01). Consistently, in vivo data also demonstrated that tumor growth was significantly inhibited in mice injected with HT-29-shSTAT3 cells. MVD was 9.80 ± 3.02 in the HT-29-shSTAT3 group, significantly less than that of the control group (P < 0.01). mRNA and protein levels of VEGFA and MMP2 in the HT-29-shSTAT3 group were significantly lower than in the control group (P < 0.05), but no significant difference was observed in the mRNA or protein level of FGF2 (P > 0.05). Taken together, these results demonstrate that STAT3 signaling is important to the growth of CRC and promotes angiogenesis by regulating VEGFA and MMP2 expression.

Management of Severe Burn Injuries in Neonates

Although rare, burns suffered by neonates can be fatal. Many complex difficulties are faced during the management of burns in neonates because of the neonate's complex physiological and pathological changes. We compiled a retrospective review from the treatment of four burned neonates (including a premature neonate). All four neonates suffered bath-related burns in the hospital as a result of careless nursing when being bathed. The total body surface area burned ranged from 1 to 60% in these patients, and all survived the burn injury. All the patients were treated in the Burn Intensive Care Unit with close co-operation of burn surgeons and neonatologists. Based on our experience as well as a review of literature, management recommendations are proposed as the following: 1) prompt and aggressive fluid resuscitation, 2) early administration of oxygen and keeping the patient warm, 3) application of specific biological dressing and recombinant human growth hormone if necessary, 4) establishment of a multidisciplinary team, and 5) removal of necrosis tissue early and aggressively. Furthermore, a very important issue is also discussed, which is about the prevention of newborn burns in the neonate unit in developing countries.

Functional analysis of the interleukin-1-receptor-associated kinase (IRAK-1) in interleukin-1 beta-stimulated nuclear factor kappa B (NF-kappa B) pathway activation: IRAK-1 associates with the NF-kappa B essential modulator (NEMO) upon receptor stimulation

The interleukin-1 (IL-1)-receptor-associated kinase (IRAK-1) is essential for IL-1-stimulated nuclear factor kappa B (NF-kappa B) activation. To study the role of IRAK-1 in IL-1 beta signalling, we have generated a set of IRAK-1 variants that express distinct domains of IRAK-1 either alone or in combination and have examined their effects on an NF-kappa B-responsive reporter in HeLa cells. Unlike full-length IRAK-1, the deletion mutants were unable to activate NF-kappa B in the absence of cytokine stimulation. However, an IRAK-1 variant lacking only the N-terminal domain retained the ability of the full-length protein to potentiate both IL-1 beta and tumour necrosis factor alpha (TNF alpha)-induced NF-kappa B activation. In contrast, expression of the N-terminus or the C-terminus of IRAK-1, or a fusion protein incorporating both domains, inhibited both IL-1 beta- and TNF alpha-induced effects. Expression of an IRAK-1 variant lacking only the C-terminal domain preferentially inhibited IL-1 beta versus TNF alpha-induced NF-kappa B activation. These data suggest that the C-terminal domain may link IRAK-1 to downstream signalling components common to both the IL-1 and TNF pathways. Furthermore, we have demonstrated that endogenous IRAK-1 becomes phosphorylated upon IL-1 beta treatment and can be detected along with NF-kappa B essential modulator (NEMO) and I kappa B kinase beta (IKK beta) in high-molecular-mass complexes of 600-800 kDa. Moreover, IRAK-1 could be detected in NEMO immunoprecipitates from IL-1 beta-stimulated cells. We conclude that IRAK-1 mediates IL-1 beta signal transduction through a ligand-dependent association of IRAK-1 with the IKK complex.

Glutathione transferase pi its minimal promoter and downstream cis-acting element

Fragments of the human glutathione S-transferase pi gene and 15 kb of its 5' flanking region have been fused to the chloramphenicol acetyl transferase (CAT) reporter gene. Transfection into a number of human cell lines (Hela, HepG2, MCF7 and EJ) has demonstrated that the AP1 binding site, located between nucleotides -58 and -65 (Cowell et al. 1988. Biochem. J. 255, 79-83), is essential for basal level promoter activity. We have also identified a positive cis-acting DNA element between nucleotides +8 and +72 which seems to be part of the promoter. No other regulatory activity was identified within the 17 kb analyzed.

Control of expression of the human glutathione S-transferase pi gene differs from its rat orthologue

We have examined regulation of the glutathione S-transferase pi gene by transient expression assay, and find that a fragment from 8 to 99 bp upstream of the cap site promotes transcription, but there is no evidence for any enhancer activity in a further 6 kb of flanking sequence. Analysis of this sequence by reference to a primate sequence database and Southern blotting revealed that as much as 5 kb of this flanking DNA were composed of repetitive insertion elements including an Alu and a LINE 1 repeat. The promoter fragment has been sequenced (Cowell et al (1988) Biochem. J. 255, 79-83) and contains a consensus AP1 binding site; in some cases, these have been associated with transcriptional induction by phorbol esters and ras oncogenes. We measured the steady state levels of glutathione S-transferase pi mRNA in human cell lines which were known to express ras oncogenes and compared them to human cell lines which have not been identified with ras activation. There was no correlation between expression of activated ras and expression of glutathione S-transferase pi mRNA. Treatment of HeLa cells, HepG2 cells and a small cell lung carcinoma line, GLC 8, with the phorbol ester 12-O-tetradecanoylphorbol 13-acetate failed to alter the steady state levels of endogenous glutathione S-transferase pi mRNA. The differences between these results and those of similar studies on rat glutathione S-transferase subunit 7, a structural orthologue of glutathione S-transferase pi, are discussed.