Zoledronic acid and alendronate sodium and the implications in orthodontic movement.

OBJECTIVE: To evaluate orthodontic tooth movement (OTM) in rats treated with two types of bisphosphonates (BPs), alendronate sodium (A) and zoledronic acid (Z). DESIGN: In all, 15 male Wistar rats were randomly divided into three groups. Group OTM+A: orthodontic tooth movement and subcutaneous administration of alendronate sodium (2.5 mg/kg); Group OTM+Z: orthodontic tooth movement and subcutaneous administration of zoledronic acid (0.02 mg/kg), and Group OTM: orthodontic tooth movement and subcutaneous injection of saline. The BPs were administered once a day during 25 days before OTM started and during 10 days of OTM. The left upper first molar was moved with a stainless-steel closed coil spring which delivered an initial force of 0.4N. OTM was measured with a digital caliper comparing the moved and the contralateral side. The histomorphometric analysis counted the number of osteoclasts, inflammatory cells, blood vessels and fibroblasts (n/104  m2 ) in periodontal ligament (PDL) of the distobuccal root. RESULTS: A reduction of 58.3% of OTM was found in Group OTM+A and 99.6% in Group OTM+Z, when compared with Group OTM. There was a significant decrease of osteoclasts and inflammatory cells in BP-treated groups. Blood vessels and fibroblastic cells decreased mainly in Group OTM+Z. CONCLUSION: Alendronate sodium and zoledronic acid have similar effects on the periodontal tissue during orthodontic treatment in rats. Especially, zoledronic acid can affect orthodontic tooth movement.

Effect of Calendula officinalis cream on achilles tendon healing.

In recent years, the scientific community has undertaken research on plant extracts, searching for compounds with pharmacological activities that can be used in diverse fields of medicine. Calendula officinalis L. is known to have antioxidant, anti-inflammatory, antibacterial, and wound healing properties when used to treat skin burns. Therefore, the purpose of this study was to analyze the effects of C. officinalis on the initial phase of Achilles tendon healing. Wistar rats were separated in three groups: Calendula (Cal)-rats with a transected tendon were treated with topical applications of C. officinalis cream and then euthanized 7 days after injury; Control (C)-rats were treated with only vehicle after transection; and Normal (N)-rats without tenotomy. Higher concentrations of hydroxyproline (an indicator of total collagen) and non-collagenous proteins were observed in the Cal group in relation to the C group. Zymography showed no difference in the amount of the isoforms of metalloproteinase-2 and of metalloproteinase-9, between C and Cal groups. Polarization microscopy images analysis showed that the Cal group presented a slightly higher birefringence compared with the C group. In sections of tendons stained with toluidine blue, the transected groups presented higher metachromasy as compared with the N group. Immunocytochemistry analysis for chondroitin-6-sulfate showed no difference between the C and Cal groups. In conclusion, the topical application of C. officinalis after tendon transection increases the concentrations of collagen and non-collagenous proteins, as well as the collagen organization in the initial phase of healing.

Arrabidaea chica extract improves gait recovery and changes collagen content during healing of the Achilles tendon.

INTRODUCTION: Tendon lesions are still a serious clinical problem. The leaves of the Bignoniaceae Arrabidaea chica (Humb. & Bonpl.) B. Verlot. (syn. Bignonia chica (Bonpl.)) have been used in traditional medicine and described in the literature for its healing properties. However, no study has shown the effects of A. chica during tendon healing. The aim of this study was to investigate the healing properties of the A. chica leaves extract on tendons after partial transection. METHODS: A partial transection in the tension region of the Achilles tendon of rats was performed with subsequent posterior topical application of A. chica extract (2.13g/mL in 0.85% saline solution) at the site of the injury. The animals (n=154) were separated into 7 groups: N - rats with tendons without transection; S7, S14 and S21 - rats with tendons treated with topical applications of saline for 7 days and sacrificed on the 7th, 14th and 21st days after surgery, respectively; A7, A14 and A21 - rats with tendons treated with topical applications of the plant extract. The transected regions of the tendons were analyzed through biochemical, morphological and functional analyses. To evaluate the type and concentration of collagen, Western blotting for collagen types I and III was performed, and the hydroxyproline concentration was determined. The participation of metalloproteinases (MMP)-2 and -9 during tendon remodelling was investigated through zymography. Gait recovery was analyzed using the catwalk system. The organization of the extracellular matrix and morphometry were detected in sections stained with haematoxylin-eosin. RESULTS: The application of A. chica extract in the region of tendon injury led to an increase in the amount of hydroxyproline (mg/g tissue) on the 7th (91.5±18.9) and 21st (95.8±11.9) days after the tendon lesion relative to the control groups treated with saline (S7: 75.2±7.2; and S21: 71.9±7.9). There were decreases in collagen types I and III (as determined by densitometry) in the groups treated with the plant extract 7 days after injury (type I: 103.9±15.9; type III: 206.3±8.1) compared to the saline-treated groups (type I: 165.2±31.1; type III: 338.6±48.8). The plant extract stimulated the synthesis of MMP-2 on the 21st day after the lesion and decreased the amount of latent and active isoforms of MMP-9 on the 14th day. Analysis by the catwalk system (max contact intensity) showed that the A. chica extract improved the gait of rats on the 7th day of the healing process when compared to the saline group. CONCLUSIONS: The use of A. chica extract during the healing process of the tendon leads to an increase in collagen content and improved gait recovery. Further studies will be performed to analyze the effect of this plant extract on the organization of the collagen bundles of tendons after lesions and to study its probable anti-inflammatory effect.

Viability of nerve grafts preserved in different storage medium: ultrastructural features

We investigated the ultrastructural organization of transplanted autologous grafts after storage in two different solutions. Male Wistar rats were divided into groups to obtain normal tibial nerves, freshly transplanted nerves, and nerves stored in Wisconsin/Belzer or Collins solution for 24 or 72 hours at 4 °C and transplanted (W1, W3, C1, C3). After storage or transplantation, the specimens were processed for ultrastructural analysis. All grafts showed alterations in collagen fiber organization in the endoneurial space compared to normal nerves. These fibers were more loosely organized among nerve fibers, a finding that was significantly more marked in group C3 compared to groups W1 and W3. Important alterations were also observed in the myelin sheath structure of grafts stored in the two media. These changes were characterized by separation of the lipid lamellae, clearly visible in larger diameter nerve fibers. These findings were more marked and frequent in the C1 and C3 groups compared to the W1 and W3 groups. Ultrastructural analysis showed better preservation of Schwann cells and other elements that support axonal regeneration for grafts stored in Wisconsin/Belzer solution. These results support ongoing studies for the formulation of storage solutions that permit the creation of nerve banks for heterologous transplantation.

The effect of age on the structure and composition of rat tendon fibrocartilage.

Biochemical and morphological aspects of fibrocartilages of calcaneal and deep digital flexor tendons in rats aged 30, 180 and 730 days were analyzed. In both tendons a stronger staining with Alcian blue, indicating the presence of proteoglycans, was detected in rats of 30 and 180 days. In animals 730 days old, it was restricted to the pericellular area. Ultrastructural analysis showed a more prominent pericellular matrix in calcaneal tendon compared to the deep digital flexor tendon. The biochemical analysis showed higher levels of proteins and glycosaminoglycans in the calcaneal tendon of 30-day-old rats compared to older rats. In the deep digital flexor tendon, no significant differences were observed between ages. The small proteoglycan, fibromodulin, was detected in both tendons of all ages, but in young rats it appeared to be running as a 210 kDa component, probably due to the association with collagen chains or self-association.

Comparative ultrastructural analysis of different regions of two digital flexor tendons of pigs.

Tendons are parallel arrays of collagenous fibers which are specialized in resisting and transmitting tensile forces. In this work we examined the structure of the superficial digital flexor tendon (SDFT) and the deep digital flexor tendon (DDFT) of pigs, which are considered "wrap around" tendons and so receive compression and tension forces. In both tendons, fibrocartilaginous areas were observed in the regions subjected to compression plus frictional loading. Histological and ultrastructural analyses of the tensional region showed an extracellular matrix (ECM) rich in collagen bundles, that were all arranged in the same direction. Fibroblasts were seen closely associated with the collagen bundles. Chondrocyte-like cells and high levels of glycosaminoglycans (GAGs) were observed in the compressional regions. The collagen bundles in the compressional region were arranged in several directions and were associated with proteoglycans (PGs). The crimp pattern detected in the tensional region showed that the collagen fibrils were ordered aggregates which formed helical superstructures.

Variations in the glycosaminoglycan content, swelling properties and morphological aspects of different regions of the superficial digital flexor tendon of pigs.

The superficial digital flexor tendon of pigs is a wrap around tendon supporting compressive in addition to the tensional forces in its proximal region, and only tensional forces in the intermediate region. Clear distinctions were observed in the physical properties, composition of proteoglycan and morphology for the different regions. A greater swelling in water and a larger amount of glycosaminoglycan were found in the proximal region compared to the intermediate one. Dermatan sulfate was detected in all regions of this tendon, while chondroitin sulfate was prominent only near the bone. In the toluidine blue stained sections, intense metachromasy was observed in the sites under compressive forces, especially in the portion close to the bone. Chondrocyte like cells were also observed in these arms. Crimp morphology, observed in the intermediate region, exhibited a clearly sloped aspect in relation to the main axis of the tendon. Elastic fibers were found in all regions, and were disposed in different directions in the areas under compressive forces, and parallel to the collagen bundles in the region under tension. These results reinforce the idea that mechanical forces contribute to a differentiated composition and organization of the extracellular matrix of tendons.

Is there a relationship between the state of aggregation os small proteoglycans and the biomechanical properties of tissues?

The small proteoglycans fibromodulin and decorin may play an important role in regulating collagen fibrillogenesis and interactions with growth factors. Here, we describe the presence of these proteoglycans in cartilage submitted to different biomechanical forces. Fibromodulin from chicken and bovine articular cartilage was shown to self-associate. The different states of fibromodulin aggregation due to disulfide bonding demonstrable in different regions of the same joint suggest that the presence of different biomechanical forces results in the differential expression of small proteoglycans. A 250-kDa complex found in chicken tibiotarsal cartilage, which migrates as a 59-kDa component in SDS-PAGE under reducing conditions, and which was recognized by anti-fibromodulin antibodies, was not demonstrable in tarsometatarsal cartilage where a different fibromodulin complex has been recently demonstrated. Biglycan and decorin were not expressed in the same way in different regions of the bovine knee joint, suggesting that there is a relationship between the expression of small proteoglycans and the different biomechanical properties of a tissue.