Application of a Purified Protein From Natural Latex and the Influence of Suture Type on Achilles Tendon Repair in Rats.

BACKGROUND: The prolonged tendon-healing process, the high costs associated with treatment, the increase in the number of injuries over the past decades, and the lack of consensus on the optimal treatment of tendon injuries are a global problem. Restoring the normal tendon anatomy and decreasing the healing time are key factors for treatment advancement. HYPOTHESIS: Application of a purified protein from natural latex (PPNL) accelerates the healing process, increasing collagen synthesis and decreasing metalloproteinases. PPNL associated with a simpler suture technique should decrease the healing time. STUDY DESIGN: Controlled laboratory study. METHODS: Injury, surgery, and treatment with PPNL were conducted with male Sprague-Dawley rats. Two suture techniques were used: U-suture, a simpler and lesser traumatic technique, and Kessler-Tajima, to avoid strangulation of the microcirculation. Achilles tendons were completely sectioned, and 100 µL of 0.1% PPNL was applied on the tendon during surgery. Tendon morphology, distribution, and quantity of collagen types I and III, as well as expression of TIMP-1, TIMP-2, MMP-2, and MMP-9 and ultrastructural aspects of cells and collagen fibrils, were assessed after 2 and 4 weeks. RESULTS: PPNL treatment improved collagen type I synthesis and reduced MMP-2 expression. All groups showed a 6.8-times increase in tendon weight as compared with the control group after 2 weeks and a 5.2-times increase after 4 weeks. All groups showed an increase in diameter after 4 weeks, except for the ones treated with PPNL, which showed a slight reduction in diameter. The peak of concentration of collagen fibrils with a 80-nm diameter was 27.79% in the control group; all other experimental groups presented fibrils between 50 and 60 nm. However, the best results were observed with Kessler-Tajima suture associated with PPNL. CONCLUSION/CLINICAL RELEVANCE: There are no known medicines or substances capable of aiding the tendon healing process besides surgery. The discovery of a substance able to improve this process and decrease its duration represents an important advancement in orthopaedic medicine.

Morphological Characterization of the Myenteric Plexus of the Ileum and Distal colon of Dogs Affected by Muscular Dystrophy.

Duchenne-like muscular dystrophy (canine dystrophinopathy) is a hereditary degenerative disease characterized by muscle changes similar to those described for Duchenne muscular dystrophy (DMD) and by alterations in the smooth muscles of the gastrointestinal tract. Some authors have suggested that these abnormalities may be associated with intestinal motility. This study analyzed the nitrergic and cholinergic neurons and P2X7 receptor expression in the myenteric plexus of the ileum and distal colon of dogs with muscular dystrophy. Immunohistochemical techniques were used to detect nitric oxide synthase (NOS) and acetylcholine transferase (ChAT) expression and to label all HuC/D- and P2X7 receptor-immunoreactive (IR) neurons. Transmission electron microscopy and basic histology were performed for further analysis. The results showed that nitrergic neurons exhibited a Dogiel type I morphology in the ileum and distal colon. The neuronal profile results showed that there were fewer NOS-, ChAT-, and HuC/D-IR neurons in the ileum than in the distal colon in the dystrophic (DT) dogs. Additionally, there were more NOS-, ChAT- and HuC/D-IR neurons per ganglion in the distal colon than in the ileum. The P2X7 receptor-expressing neurons colocalized with nitrergic and cholinergic neurons. Transmission and light microscopy revealed collagen between the muscle fibers, between the circular and longitudinal muscle layers and within the myenteric ganglia of dogs with muscular dystrophy. These findings provide a morphological description of the myenteric neurons in the ileum and distal colon of these DT dogs and may contribute to a better understanding of the gastrointestinal disorders found in patients with DMD. Anat Rec, 301:673-685, 2018. © 2017 Wiley Periodicals, Inc.

Distribution of the P2X2 receptor and chemical coding in ileal enteric neurons of obese male mice (ob/ob).

AIM: To investigate the colocalization, density and profile of neuronal areas of enteric neurons in the ileum of male obese mice. METHODS: The small intestinal samples of male mice in an obese group (OG) (C57BL/6J ob/ob) and a control group (CG) (+/+) were used. The tissues were analyzed using a double immunostaining technique for immunoreactivity (ir) of the P2X2 receptor, nitric oxide synthase (NOS), choline acetyl transferase (ChAT) and calretinin (Calr). Also, we investigated the density and profile of neuronal areas of the NOS-, ChAT- and Calr-ir neurons in the myenteric plexus. Myenteric neurons were labeled using an NADH-diaphorase histochemical staining method. RESULTS: The analysis demonstrated that the P2X2 receptor was expressed in the cytoplasm and in the nuclear and cytoplasmic membranes only in the CG. Neuronal density values (neuron/cm(2)) decreased 31% (CG: 6579 ± 837; OG: 4556 ± 407) and 16.5% (CG: 7796 ± 528; OG: 6513 ± 610) in the NOS-ir and calretinin-ir neurons in the OG, respectively (P < 0.05). Density of ChAT-ir (CG: 6200 ± 310; OG: 8125 ± 749) neurons significantly increased 31% in the OG (P < 0.05). Neuron size studies demonstrated that NOS, ChAT, and Calr-ir neurons did not differ significantly between the CG and OG groups. The examination of NADH-diaphorase-positive myenteric neurons revealed an overall similarity between the OG and CG. CONCLUSION: Obesity may exert its effects by promoting a decrease in P2X2 receptor expression and modifications in the density of the NOS-ir, ChAT-ir and CalR-ir myenteric neurons.