Pathological, Bacteriological and Prevalence Studies Of Ovine Footrot

Ovine footrot, is a disease associated with infection by the bacterium Dichelobacter nodosus. It is a disease that limits the productivity or sheep-farming enterprises throughout the world. Both wool production and body weight are adversely affected during the clinical phase of the infection. Ovine footrot has become an important contagious disease in Malaysia. The first confirmed case of footrot was reported in a government sheep farm in mid-198Os. The disease is now present ill other farms throughout the country, and local vaccine is being used to reduce the disease. Previous studies have identified D. nodosus in three sheep farms ill Malaysia and only serogroup B was identified. The possible presence of other D. nodosus serogroups and scrotypes is unknown. This study attempts to isolate and identify the unknown serogroups and serotypes so as develop a better vaccine candidate using local isolates of D. nodosus. Eight sheep farms were investigated in this study. Four sheep farms were found to be infected with D. nodosus. Two hundred and ninety-three D. nodosus isolates were obtained from 741 foot samples. Five serogroups were identified in Malaysia. This is the first study where serogroups A, C, F and I with their serotypes AI, A2, CI, FI and F2 were identified in the infected sheep farms. Serogroup B was the predominant serogroup isolated (78.2%) while the isolation percentages for serogroups F, A, I and C were 7.9%, 7.5%, 3.8% and 2.7% respectively. The information on the pathogenesis of the disease is still lacking despite previous studies on ovine footrot. Interdigital cutaneous changes associate with footrot in sheep is not well documented. The disease was induced experimentally in sheep by topical application of bacterial isolates on the interdigital skin of the hoof, and light and electron microscopy studies of the lesions were conducted. Virulent footrot was observed by a gross progressive separation of the horny tissues from the soft tissues. On day 21 post inoculation (p.i.), a complete separation of the hoof from the underrunning structures and lameness were evident. The benign footrot was observed with mild interdigital dermatitis and all infected feet completely recovered on day 21 p.i.. Histopathological changes in virulent footrot were observed in the interdigital skin layers and hoof matrix. These ranged from acute dermatitis to hyperkeratosis, parakeratosis and acanthosis of the epidermis. Oedema and leukocytic infiltration with neutrophils, macrophages and scanty lymphocytes were also evident in the dennis. Furthermore, vasculitis and perivascular cuffing, lymphangitis and inflammation of the sweat glands were observed in the dermis. The histopathological changes of benign footrot were less severe than virulent form in the epidermis and there were no pathological changes in the dermis. In scanning electron microscopy, a severe zone of lysis appearing as a surface depression around bacteria in the horny layer of the interdigital skin of the hoof was detected in virulent footrot, while this lesion was less severe in the benign form. Transmission electron microscopy revealed degeneration in the epiderm is and dermis. Degeneration in the basal cell layer of the epidermis and the basement membrane in virulent form of footrot, which have not been reported previously was observed in this study. Dichelobacter nodosus was observed in the lesions of the epidermis and dermis of virulent footrot. Its' isolation from characteristic foot lesions indicated that it was associated with footrot. Immunohistochemistry observations validate the relationship between the lesions seen in footrot and virulent D. nodosus. Immunogold staining technique facilitates to detection and localisation of D. nodosus for electron microscopy. Specific reactions were labelled in components and the matrix of epidermis and dermis of the interdigital skin. Dichelobacter nodosus antigen labelled with 5 nm gold particles was observed in the intracellular and intercellular spaces of the epidermis. This is the first report where immunogold labelling technique have been used in the study of footrot lesions in sheep for electron microscopical observations. The total monthly rainfall and mean daily temperature have a relation to the prevalence rate of the disease. These conditions provide suitable environment propagation of D. nodosus. The overall prevalence of footrot in the eight farms investigated was 3.3%. The highest prevalence was recorded in April (0.8%), while the lowest in August (0.3%) in IHK farm by survey study. Observations described in this study were made to define the prevalence are related to seasonal conditions, but the effect of rainfall overrides all other factors for footrot to occur. Adults were more susceptible than weaners. No cases were detected in preweaners. The prevalence by sex which was 4.4% in the male and 7.7% in the female was significant (p=O.009). No significant difference in prevalence rates between breeds was detected

Identification of adipogenesis and osteogenesis pathways of differentiated bone marrow stem cells in vitro in rabbits

Transdifferentiation is a process whereby a cell type committed to and progressing along a specific developmental lineage switches into another cell types. The objective of this study was to assess whether rabbit mesenchymal stem cells (rMSCs) precommitted to give mesenchymal cell lineage transdifferentiate in response to inductive extracellular cues to expand adult MSCs. Bone mesenchymal stem cells (BMSCs) obtained from ilium of adult male rabbit comprised heterogeneous groups of cells after seeding and growing in culture plates. After initial plating, the adherent cells exhibited small rounded, spindle-shaped and exhibited fibroblast-like morphology in reaching confluence. Rabbit BMSCs differentiated into adipocytes and osteocyte as a accumulation of intracellular lipid droplets and calcium deposition throughout the culture after 21 days

Neurobiological observations of bone mesenchymal stem cells in vitro and in vivo of injured sciatic nerve in rabbit

The PKH26 is a fluorescent lipophilic dyes used for the study of Asymmetric cell Divisions (ASDs) and efficiently purifies the stem cell fraction. The aim of this study was to explore the neurobiological characteristics in vitro and in vivo and tracking fate of the transplanted rabbit Bone Marrow-Mesenchymal Stem Cells (rBM-MSCs). A fluorescent microscope was used to determine the changes in cell size, fluorescence intensity during tissue culture, track cell divisions and the distribution of PKH26 dye between daughter cells. The results showed the identification of ASDs based on fluorescence intensity of the PKH26 dye was distributed equally between daughter cells at each division in vitro. The labeling BMSCs with PKH26 showed within the wall of the neurons in the dorsal root ganglia in vivo. Labeled BMSCs which are fibroblastic-like cells in P4 showed oval shaped and less density than P2. Direct examine of the labeled BMSCs in the cryosections at 16 weeks post operation showed the BMSCs were differentiated and appeared as like Schwann cells in an anastomosed sciatic nerve in the Local Treated Group (LTG). In the Systemic Treated Group (STG) sections, the labeled BMSCs were migrated to the anastomosed sciatic nerve, ipsilateral lumber dorsal root ganglia resembling glial and stellate cells and some of the labeled cells migrated to the anterior horn of spinal cord (motor neuron). In conclusion, the biological behaviors of BMSCs in vitro and in vivo showed highly mitosis at P2, activated fibroblast-like cells, differentiated to functional myelinating Schwann-like cells in LTG. The BMSCs in STG migrated and engrafted at the dorsal root ganglia as a neuron and glial cell, glial cells and satellite in the spinal cord

Bone marrow stromal cells implantation and suture repair of peripheral nerve: a comparative study of functional, histopathological, morphometric and relative gastrocnemius muscle weight in rabbits

The peripheral nervous system has the ability to regenerate after injury. Peripheral nerve injuries are caused by penetrating injury, crush, traction and ischemia compression. However, the availability of various nerve coaptation and other techniques for the attainment of functional nerve regeneration is still inadequate. The objective of this study was to compare the effectiveness of bone marrow stromal cells (BMSCs) implantation and epineural nerve suture on peripheral nerve regeneration in a rabbit model. Ten male New Zealand white rabbits were divided into two groups. In the primary epineural repair group (control group), the left sciatic nerve was skeletonized from the sciatic notch to the point of bifurcation, with the nerve been transected at the mid-shaft of the femoral bone and repaired with six epineural sutures. In the treated group, the epineural repaired nerve was implanted with BMSCs in the proximal and distal segments of the transected sciatic nerve. Assessment of the nerve regeneration was based on functional (motor and sensory), histological and morphometric criteria, including the number of myelinated nerve fibers, nerve fiber diameter, axon diameter, myelin sheath thickness, g ratio and relative gastrocnemius muscle weight. The results of the examination showed that the treated group had the best regeneration and functional recovery