acid-phosphatase and Fibrosis

Up to now, studies of exercise-induced cardiac arrhythmia have focused primarily on the working myocardium, with few studies examining to the cardiac conduction system where the rhythmic and synchronized contraction of the heart is initiated. To explore whether the cardiac conduction system is involved in the exercise-induced cardiac injury, we performed histological analysis of sinoatrial node, atrioventricular node and Purkinje fibers and tested the level of structural protein cardiac troponin T and Connexin 43 in Sprague Dawley rats following repeated exhaustive exercise. We found increased collagen deposition, hyperplasia interstitialis, and enhanced activity of lactate dehydrongenase and acid phosphatase in the cardiac conduction system following repeated exhaustive exercise. Mitochondrial alterations, enlarged area of intercalated disc and disappearance of gap junctions were additionally observed through electron transmission microscopy. In addition, significant decreases in cardiac troponin T and Connexin 43 were present in the cardiac conduction system in response to repeated exhaustive exercise. All of these findings demonstrate that repeated exhaustive exercise induces ischemic alterations, damage to cytoskeleton and gap junctions, and tissue fibrosis in the cardiac conduction system in rats. These data may shed a new light on the mechanism of exercised-induced cardiac injury and arrhythmia.

Topics: Acid Phosphatase; Animals; Arrhythmias, Cardiac; Connexin 43; Down-Regulation; Fibrosis; Heart Conduction System; L-Lactate Dehydrogenase; Male; Myocardium; Physical Conditioning, Animal; Random Allocation; Rats, Sprague-Dawley; RNA, Messenger; Swimming; Troponin T

To determine the key biological events occurring during implant failure and then we use this knowledge to develop new biology-based strategies that improve osseointegration.. Wild-type and Axin2(LacZ/LacZ) adult male mice underwent oral implant placement, with and without primary stability. Peri-implant tissues were evaluated using histology, alkaline phosphatase (ALP) activity, tartrate resistant acid phosphatase (TRAP) activity and TUNEL staining. In addition, mineralization sites, collagenous matrix organization and the expression of bone markers in the peri-implant tissues were assessed.. Maxillary implants lacking primary stability show histological evidence of persistent fibrous encapsulation and mobility, which recapitulates the clinical problems of implant failure. Despite histological and molecular evidence of fibrous encapsulation, osteoblasts in the gap interface exhibit robust ALP activity. This mineralization activity is counteracted by osteoclast activity that resorbs any new bony matrix and consequently, the fibrous encapsulation remains. Using a genetic mouse model, we show that implants lacking primary stability undergo osseointegration, provided that Wnt signalling is amplified.. In a mouse model of oral implant failure caused by a lack of primary stability, we find evidence of active mineralization. This mineralization, however, is outpaced by robust bone resorption, which culminates in persistent fibrous encapsulation of the implant. Fibrous encapsulation can be prevented and osseointegration assured if Wnt signalling is elevated at the time of implant placement.

Topics: Acid Phosphatase; Alkaline Phosphatase; Alveolar Process; Animals; Axin Protein; Bone Matrix; Bone Resorption; Calcification, Physiologic; Collagen; Connective Tissue; Dental Implantation, Endosseous; Dental Implants; Dental Restoration Failure; Fibrosis; Isoenzymes; Male; Maxilla; Mice; Models, Animal; Osseointegration; Osteoblasts; Osteoclasts; Osteogenesis; Periodontium; Periosteum; Tartrate-Resistant Acid Phosphatase; Wnt Signaling Pathway

Neurofibromatosis type 1 (NF1) is a common genetic condition caused by mutations in the NF1 gene. Patients often suffer from tissue-specific lesions associated with local double-inactivation of NF1. In this study, we generated a novel fracture model to investigate the mechanism underlying congenital pseudarthrosis of the tibia (CPT) associated with NF1. We used a Cre-expressing adenovirus (AdCre) to inactivate Nf1 in vitro in cultured osteoprogenitors and osteoblasts, and in vivo in the fracture callus of Nf1(flox/flox) and Nf1(flox/-) mice. The effects of the presence of Nf1(null) cells were extensively examined. Cultured Nf1(null)-committed osteoprogenitors from neonatal calvaria failed to differentiate and express mature osteoblastic markers, even with recombinant bone morphogenetic protein-2 (rhBMP-2) treatment. Similarly, Nf1(null)-inducible osteoprogenitors obtained from Nf1 MyoDnull mouse muscle were also unresponsive to rhBMP-2. In both closed and open fracture models in Nf1(flox/flox) and Nf1(flox/-) mice, local AdCre injection significantly impaired bone healing, with fracture union being <50% that of wild type controls. No significant difference was seen between Nf1(flox/flox) and Nf1(flox/-) mice. Histological analyses showed invasion of the Nf1(null) fractures by fibrous and highly proliferative tissue. Mean amounts of fibrous tissue were increased upward of 10-fold in Nf1(null) fractures and bromodeoxyuridine (BrdU) staining in closed fractures showed increased numbers of proliferating cells. In Nf1(null) fractures, tartrate-resistant acid phosphatase-positive (TRAP+) cells were frequently observed within the fibrous tissue, not lining a bone surface. In summary, we report that local Nf1 deletion in a fracture callus is sufficient to impair bony union and recapitulate histological features of clinical CPT. Cell culture findings support the concept that Nf1 double inactivation impairs early osteoblastic differentiation. This model provides valuable insight into the pathobiology of the disease, and will be helpful for trialing therapeutic compounds.

Topics: Acid Phosphatase; Animals; Bone Morphogenetic Protein 2; Cell Differentiation; Cell Lineage; Cell Proliferation; Disease Models, Animal; Female; Fibrosis; Fracture Healing; Gene Deletion; HEK293 Cells; Humans; Integrases; Isoenzymes; Mice; Mice, Inbred C57BL; Mice, Knockout; Muscles; Neurofibromatosis 1; Neurofibromin 1; Osteoblasts; Osteoclasts; Osteogenesis; Pseudarthrosis; Recombinant Proteins; Reproducibility of Results; Tartrate-Resistant Acid Phosphatase; Tibia; Transforming Growth Factor beta

The present study was undertaken to determine whether there is any alteration in the activities of lysosomal enzymes in the liver and sera of rats during the course of carbon tetrachloride (CCl4) induced cirrhosis in rats. Cirrhosis was induced by the chronic administration of carbon tetrachloride plus phenobarbitone. N-acetyl glucosaminidase, P-glucuronidase and acid phosphatase were assayed spectrophotometrically in the liver homogenates and in the sera at different stages of liver injury i.e., necrosis, fibrosis, and cirrhosis. Significant increase in the "basal" activities of N acetyl glucosaminidase, beta-glucuronidase, and acid phosphatase were observed in the livers of rats during the course of development of cirrhosis. As the liver injury progressed from necrosis to cirrhosis, the 'free' activities of these three enzymes also increased. The 'total' activities of the enzymes studied were either decreased or remained unaltered. The increased 'free' activities of the lysosomal enzymes in the liver of CCl4 treated rats may contribute to cellular autophagy and tissue catabolism, which may subsequently lead to cirrhosis.

Topics: Acetylglucosaminidase; Acid Phosphatase; Animals; Carbon Tetrachloride; Fibrosis; Glucuronidase; Lysosomes; Male; Rats; Rats, Wistar

In 36 male Wistar rats extrahepatic cholestasis was induced by ligation and transsection of the common bile duct. After 1, 2 and 3 weeks of cholestasis the bile flow was restored by means of a Roux-en-Y choledochojejunostomy. Plasma levels of bilirubin, alkaline phosphatase, GOT and clotting factor X were measured weekly. Liver biopsies were taken at the time of restored bile flow as well as 3 and 8 weeks thereafter. Histochemical reaction for lactate dehydrogenase activity and Sirius Red F3BA staining were used as measure for functional liver parenchyma and collagen, respectively. Acid phosphatase, alkaline phosphatase and 5'-nucleotidase activities as well as the glycogen content were demonstrated in cryostat sections of the same biopsies. After 1, 2 and 3 weeks of common bile duct obstruction, levels of bilirubin, alkaline phosphatase and GOT significantly increased, whereas levels of clotting factor X decreased. RBF resulted in normalization of all these levels to control range. The volume density of functional parenchyma was found to be reduced to 90%, 73% and 64% of the control values following 1, 2 and 3 weeks of common bile duct obstruction respectively, returning to 96%, 94% and 88% at 8 weeks, respectively, after restored bile flow. The collagen content increased significantly during cholestasis up to 5-fold after 3 weeks of common bile duct obstruction. After restored bile flow, a slight decrease of collagen was measured in some animals but in none of the three groups a return to normal values appeared. Cholestasis induced an alteration in localization and/or activity of the three enzymes analyzed as well as a depletion of glycogen stores. All changes in activity and distribution pattern of the three enzymes, as well as the glycogen depletion during common bile duct obstruction normalised after restored bile flow was performed. However, the longer common bile duct obstruction had existed, the longer period was needed for full recovery. In conclusion, even after 3 weeks of common bile duct obstruction the parenchyma/stroma relationship grossly normalized after restored bile flow with an almost complete restoration of the parenchyma and a concomitant recovery of liver function. However, collagen once formed, did not disappear but remained as more condensed septa, which apparently did not interfere with normal function.

Topics: 5'-Nucleotidase; Acid Phosphatase; Alkaline Phosphatase; Anastomosis, Roux-en-Y; Animals; Bile Ducts; Choledochostomy; Cholestasis, Extrahepatic; Collagen; Fibrosis; Hematologic Tests; Homeostasis; Liver Glycogen; Male; Postoperative Complications; Rats; Rats, Wistar