[Progress on the minimally invasive surgical treatment for the acute Achilles tendon rupture].

Acute Achilles tendon rupture is a common sports injury, is currently the best treatment for acute Achilles tendon rupture there are more controversial programs in the clinical, their treatment is divided into conservative treatment and surgical treatment. Conservative treatment for a long time, and then the higher Achilles tendon rupture rate, postoperative recovery slow. There are a number of complications traditional open surgery, and minimally invasive surgery in recent years developed a new technology that minimizes the exposure of the wound, reduce surgical trauma scope, shorten the operation time and reduce wound infection rate increasing importance in clinical practice, worthy of recommendation.

Growth/differentiation factor-5 induces osteogenic differentiation of human ligamentum flavum cells through activation of ERK1/2 and p38 MAPK.

Ossification of ligamentum flavum (OLF) is a pathological ectopic ossification in the spinal ligament, leading to spinal canal stenosis, but little was known about its pathogenesis. A previous study has found growth/differentiation factor (GDF)-5 expression at ossified sites of the ligaments from OLF patients. This study aimed to investigate the osteogenic effects of GDF-5 on cultured human ligamentum flavum cells (LFCs). LFCs were isolated from human spinal ligamentum flavum, and treated with or without recombinant human (rh) GDF-5. Alkaline phosphatase (ALP) activity was measured. Expression of osteocalcin was assessed by reverse transcriptase-PCR, Western blotting and immunofluorescence. Matrix mineralization was assessed by alizarin red staining. Activation of mitogen-activated protein kinases (MAPK) ERK1/2, p38 and JNK were detected by Western blotting. We found that rhGDF-5 treatment increased ALP activity and osteocalcin expression in a time- and dose-dependent manner, and induced mineralized nodule form. In addition, rhGDF-5 challenge mediated the ERK1/2 and p38 activation but not JNK. Inhibiting this activation pharmacologically, using U0126, a ERK1/2 inhibitor, or SB203580, a p38 inhibitor, resulted in significantly lower ALP activity and osteocalcin protein expression. The present study shows that rhGDF-5 induces osteogenic differentiation of human LFCs through activation of ERK1/2 and p38 MAPK. These findings give some new insight into the pathogenesis of OLF.

The effect of leptin on the osteoinductive activity of recombinant human bone morphogenetic protein-2 in nude mice.

OBJECTIVE: To investigate the effect of leptin in the model of ectopic bone formation that utilizes subcutaneously implanted recombinant human bone morphogenetic protein-2 (rhBMP-2)-containing type I collagen discs. METHODS: This study was performed in the Clinical Research Center, Southern Medical University, Guangzhou, China from November 2008 to June 2009. A single dose of 20 ul saline (group A), 20 ug leptin (group B), 2 ug rhBMP-2 (group C), 2 ug rhBMP-2 + 20 ug leptin (group D), and type I collagen disks as a carrier were mixed, and subcutaneously implanted into the back of nude mice (n=12). The effect of ectopic bone formation was evaluated by radiography, dual-energy X absorptiometry, biochemical examination of alkaline phosphatase (ALP) activity, histological observation, and semi-quantitative evaluation 4 and 8 weeks after surgery. RESULTS: At 4 and 8 weeks after operation the radiographs, bone mass density, ALP, and histology values showed significant intragroup and intergroup differences, with those at 8 weeks being higher than those at 4 weeks. CONCLUSION: Our results indicated that the sustainedly released material with collagen as a carrier combined treatment with leptin and rhBMP-2 has a very good osteoinductive activity. Leptin is a positive modulator for the osteoinductive efficacy of BMPs, they have synergistic effect. Its mechanisms are probably related to promote the formation of new-vessels and proliferation/ differentiation of many kinds of cells.

Leptin expression by heterotopic ossification-isolated tissue in rats with Achilles' tenotomy.

OBJECTIVE: To set up heterotopic ossification (HO) models according to McClure and determine whether leptin messenger ribonucleic acid (mRNA) and protein are expressed in HO-isolated tissue. METHODS: This study was performed in the Department of Spine and Orthopedics, Southern Medical University, Guangzhou, China from November 2007 to June 2008. Thirty-six male rats were randomly divided into sham, partial achilles' tenotomy (PAT), and achilles' tenotomy (AT) groups, with 12 rats in each group. X-ray and histological examination were carried out to ensure the formation of HO at 5 and 10 weeks after operation. Specimens from achilles tendons and surrounding tissue were taken and processed. Meanwhile, the expression of leptin mRNA (5 and 10 weeks) and protein (10 weeks) in achilles tendons and the surrounding tissue were examined respectively using reverse transcription-polymerase chain reaction assay and immunohistochemical methods. RESULTS: There were no leptin mRNA and protein expression in the sham and a weak expression in the PAT of Achilles tendons and surrounding tissue, whereas there was strong expression in the AT group. CONCLUSION: Leptin is involved in the formation of HO, its mechanisms is related to induction of bone formation and maturation through a series of cellular events, including: proliferation/differentiation of many kinds of cells, collagen synthesis, mineralization, and vascularization of the extracellular matrix.