Stereological Evaluation of Rabbit Fetus Liver after Xenotransplantation of Human Wharton's Jelly-Derived Mesenchymal Stromal Cells.

Background: In-utero xenotransplantation of stem cells in abnormal fetuses effectively treats several genetic illnesses. Objective: The current research aimed to evaluate structural and morphological alterations in the liver of rabbit fetuses following xenotransplantation of human Wharton's jelly-derived mesenchymal stromal cells (hWJ-MSCs), using a stereological technique. Methods: All hWJ-MSCs were isolated from the human umbilical cord, and their authenticity was established by flowcytometry and differentiation. At gestational day 14, the rabbits were anesthetized, and hWJ-MSCs were injected into the uteri of 24 fetuses. Twenty-two fetuses were born successfully. Ten rabbit liver specimens were prepared from injected fetuses including; eight rabbits on day three following birth and two rabbits on the 21st post-natal day. The non-injected fetuses were considered positive controls. The livers of the control and hWJ-MSCs-treated rabbits were fixed, processed, stained, and examined through stereological approaches. Results: In the hWJ-MSCs-treated group, the mean liver weight and volume increased by 42% and 78% compared to the control group. The total volume of the hepatocytes increased by 63%, and that of sinusoids by three folds in the treated rabbits. The total volume of the central veins increased by 70%. The total number corresponding to hepatocytes in the experimental group increased by 112% compared to the rabbits in the control. The total volume of the hepatocyte nuclei in the experimental group increased by 117% compared to the rabbits in the control. Conclusion: After xenotransplantation of human MSCs, host tissue microenvironments (here, the rabbit liver) were altered and these included quantitative factors corresponding to the liver tissue and hepatocyte morphometric indices.

Regenerative Effect of Bone Marrow-derived Mesenchymal Stem Cells in Thioacetamide-induced Liver Fibrosis of Rats.

The present study determined the regenerative effect of bone marrow-derived stem cells (BMSCs) on thioacetamide (TA)-induced liver fibrosis in rats. A total of 30 male Wistar rats were randomly divided into sham control and treatment groups. The rats of the sham control group were subdivided into three groups and sampled on the 14th, 18th, and 20th weeks after fibrosis induction. The rats of the treatment group were subdivided into two groups and sampled on the 4th and 6th weeks after BMSCs treatment. Fibrosis was induced by the intraperitoneal administration of 200 mg/kg of TA twice a week for a period of 14 weeks. All the animals underwent liver function tests and histopathologic evaluation 4 and 6 weeks after BMSCs transplantation. The BMSCs were characterized using osteogenic induction and reverse transcription-polymerase chain reaction. The BMSCs were plastic adherent, spindle-shaped, and positive for osteogenic differentiation. They expressed CD73 and were negative for CD45. The infiltration of inflammatory cells and deposition of collagen fibers were noticed after TA administration. A significant decline in inflammatory cells and a healing process were detected 4 weeks after cell transplantation. The amelioration in hepatic tissue was significant 6 weeks after cell therapy. Following the injection of BMSCs, a nonsignificant decrease was visible in aspartate transaminase level; however, this decline was significant for alanine aminotransferase level. The alkaline phosphatase and albumin levels showed an increasing trend after cell administration. The transplantation of BMSCs resulted in a significant regenerative effect after hepatic injuries. Therefore, it was shown that BMSCs transplantation can open a new window and be a therapy of choice in the amelioration of liver fibrosis.

Is immunosuppression, induced by neonatal thymectomy, compatible with poor reproductive performance in adult male rats?

With increasing knowledge that the immune system has a major impact on reproductive health, the potential for cells arising in organs such as the thymus to alleviate oxidative stress has been revealed. This study addresses the impact of neonatal thymectomy on male reproductive function in pubertal and adult animals. Neonatal Sprague Dawley rats were allotted to four treatments consisting of fully thymectomized, partially thymectomized, intact, and sham-operated rats. Half of the rats in each treatment were sacrificed at 40 and the other half at 80 days of age. Testicular volume, ventral prostate and spleen weight, several sperm attributes (concentration, motility, livability, membrane integrity, sperm penetration into mucus, total antioxidant capacity, mitochondrial dehydrogenase activity), plasma superoxide dismutase, glutathione, and testosterone level as well as fertility decreased in thymectomized rats. Adrenal gland weight, sperm malondialdehyde level, indices of oxidative stress, sperm abnormality, testicular and sperm lipid peroxidation, protein carbonylation, and sperm reactive oxygen species generation increased in thymectomized rats. In thymectomized rats, the testes contained high levels of malondialdehyde but low levels of glutathione and ferric-reducing antioxidant power. Epididymal sperm reactive oxygen species, blood lipid peroxidation, and oxidative stress indices in blood and spermatozoa were highest in fully thymectomized, intermediate in partially thymectomized, and lowest in both pubertal and mature control rats. Blood levels of superoxide dismutase, lipid peroxidation indices, and testosterone, and mitochondrial adenosine triphosphate and dehydrogenase activities in epididymal spermatozoa were lowest in fully thymectomized, intermediate in partially thymectomized, and highest in both pubertal and mature control rats. The data indicated that increased oxidative stress and mitochondrial dysfunction might play a role in the mechanism of immunosuppression-induced testicular and sperm abnormalities.

Hydroethanolic extract of Psidium guajava leaf for induced osteoarthritis using a guinea pig model.

We investigated the therapeutic effects of an extract of Psidium guajava (guava) leaf on experimentally induced osteoarthritis in guinea pig. The left knee of 30 male guinea pigs was anesthetized and the cranial cruciate ligament was severed. The animals were followed for 8 weeks until osteoarthritis was confirmed by radiography and histopathology. Animals were divided randomly into five groups; group 1, the ligament was severed and untreated; group 2, the ligament was severed and treated with piascledine, an extract of soybean and avocado; group 3, the ligament was severed and treated with 200 mg/kg hydroethanolic extract of guava; group 4, the ligament was severed and treated with 400 mg/kg hydroethanolic extract of guava; and group 5, control animals without surgery or extracts. Radiological and histopathological evaluations after 8 weeks showed reduced severity of osteoarthritis in the piascledine treatment group compared to group 1. The guava extract also reduce the severity of osteoarthritis compared to controls. Histopathological examination of treatment and control groups showed that treatment the guava extract improved lesions significantly. Hydroethanolic extracts of guava leaf appears to prevent osteoarthritis by inhibition of free radical formation in the knee joint.

Hydroalcoholic extract of Carum carvi L. in oral mucositis: a clinical trial in male golden hamsters.

OBJECTIVES: Several studies have attempted to prevent or improve oral mucositis (OM) but have not produced a qualified treatment yet. This study evaluates the effects of Carum carvi L. (caraway) hydroalcoholic extract (CHE) as one of the traditional medicinal plants in 5-fluorouracil (5-FU)-induced OM in golden hamsters. MATERIALS AND METHODS: OM was induced in 54 male golden hamsters by 5-FU and cheek pouch scratching. Starting from day 12, 500 and 1000 mg kg(-1) per day topical CHE were administered. Pouch histopathology score, malondialdehyde and reduced glutathione contents, and activity of myeloperoxidase plus microbial cultures of cheek pouch, antimicrobial properties of CHE, and essential oil constituents were evaluated. RESULTS: Lower histopathology score (0, 1, and 2) and malondialdehyde level, higher reduced glutathione level and activities of myeloperoxidase were detected in 1000 and 500 mg kg(-1) per day topical CHE and control groups, respectively (P < 0.001). The CHE was more potent against Staphylococcus epidermidis and Streptococcus intermedius. γ-Terpinene (37.2%) was identified as the main constituent of essential oil. CONCLUSION: The use of CHE in topical form may be associated with reduced intensity of OM. This may be due to appropriate antibacterial activity and terpinene contents.

The Healing Effect of Adipose-Derived Mesenchymal Stem Cells in Full-thickness Femoral Articular Cartilage Defects of Rabbit.

BACKGROUND: Articular cartilage defect can lead to degradation of subchondral bone and osteoarthritis (OA). OBJECTIVE: To determine the healing effect of transplantation of adipose-derived mesenchymal stem cells (Ad-MSCs) in full-thickness femoral articular cartilage defects in rabbit. METHODS: 12 rabbits were equally divided into cell-treated and control groups. In cell-treated group, 2×10(6) cells of third passage suspended in 1 mL of DMEM was injected into articular defect. The control group just received 1 mL of DMEM. Dulbecco's modified Eagles medium (DMEM) supplemented with 10% fetal bovine serum (FBS), 1% penicillin and streptomycin and 2 mM L-glutamine were used for cell culture. To induce cartilage defect, 4 mm articular cartilage full-thickness defect was created in the knee. For histological evaluation in each group (H&E, safranin-O and toluidine blue), 3 rabbits were sacrificed 4 weeks and 3 animals, 8 weeks after cell transplantation. RESULTS: In cell therapy group post-transplantation, no abnormal gross findings were noticed. Neo-formed tissues in cell-treated groups were translucent with a smooth and intact surface and less irregularity. In cell-treated group after 8 weeks post-transplantation, the overall healing score of experimental knees were superior when compared to other groups. CONCLUSION: We showed that Ad-MSCs, as an available and non-invasive produced source of cells, could be safely administered in knee osteochondral defects.

Stereological study of the effect of black olive hydroalcoholic extract on osteoporosis in vertebra and tibia in ovariectomized rats.

UNLABELLED: A cocktail of many different antioxidants might be more effective than supplementation with a single molecule, and it closely resembles the natural environment in which active compounds were found. This is the first study well-grounded in stereological examination that showed that black olive extract effectively can ameliorate the quantitative changes of the bone structure and prevented bone loss in this osteoporosis animal model. INTRODUCTION: The aim of this study was to quantitatively evaluate the effects of black olive extract consumption on treatment of ovariectomized (OVX) induced osteoporosis in rats. This is the first study well-grounded in stereological examination. METHODS: Ninety adult rats were allocated to control, sham-operated, OVX, and olive-supplemented OVX groups (received 250-, 500-, and 750-mg/kg body weight black olive hydroalcoholic extract orally) for 16 weeks. At the end of the experiment, blood samples were collected, and plasma levels of calcium, phosphorus, and alkaline phosphatase were assayed. Then, the specimens from both the tibia and fifth lumbar vertebra (L5) bones were processed, and stereological analysis was performed. RESULTS: Administration of extract resulted in decrease of alkaline phosphatase level during the treatment. After treatment of OVX rats with three doses of extract, the total number of the osteocytes revealed an increment in 500- and 750-mg/kg treated groups in comparison to the OVX group. This increment was significant only in L5. Compared to the OVX group, a significant increase was observed in the number of osteoblastsin L5 vertebra in three doses of extract-treated groups. However, this increment in tibia was statistically significant only in 750-mg/kg black olive hydroalcoholic extract-treated group. Moreover, the number of osteoclast cells were significantly decreased in vertebra and tibia in the treated groups compared to the OVX group (P < 0.05). CONCLUSION: Black olive hydroalcoholic extract effectively can ameliorate the quantitative changes of the bone structure and prevented bone loss in this osteoporosis animal model. Thus, it can be a promising candidate for treatment of accelerated bone loss especially in postmenopausal osteoporosis.

Effects of low-intensity pulsed ultrasound on healing of mandibular bone defects: an experimental study in rabbits.

Research evidence suggests that low-intensity pulsed ultrasound (LIPU) produces significant osteoinductive effects, accelerating the healing of bone defects. The authors investigated the effects of LIPU on mandibular bone defects in a rabbit model. Fifty-six adult Dutch rabbits were divided randomly into control, LIPU-1 (1MHz), and LIPU-3 (3MHz) groups. A mandibular defect was created in all rabbits. The effect of LIPU on mandibular defects was assessed by frequency (1 or 3MHz) and timing (2 and 4 weeks). Bone mineral density (BMD) was measured and stereology and histology performed; results were compared at the end of 2 and 4 weeks. LIPU-3 resulted in significantly higher bone formation compared to the control group at the end of week 4 on histological assessment (P=0.008). BMD was significantly higher at 4 weeks than at 2 weeks (P=0.03). LIPU-3 increased the numerical density of osteoblasts and osteocytes at the end of week 4 (P=0.05 and P=0.001, respectively). The results of this study are in favour of using LIPU 3MHz to accelerate mandibular bone healing. However, this study suggests that a frequency of 3MHz and the longer application of LIPU 3MHz for 4 weeks can only promote 8% mandibular bone healing in rabbits. Therefore, the use of LIPU has no really convincing, consistent clinical effects on maxillofacial bone healing.

Comparative assessment of the therapeutic effects of the topical and systemic forms of Hypericum perforatum extract on induced oral mucositis in golden hamsters.

Oral mucositis is a common and irritating complication of chemotherapy and radiotherapy for malignancies. Current treatments have failed to achieve complete remission of this complication. The St. John's wort plant (Hypericum perforatum) has long been known for its anti-inflammatory and antibacterial effects. The current study was designed to investigate the therapeutic efficacy of the topical and systemic administration of H. perforatum extract on oral mucositis. Oral mucositis was induced in 72 male golden hamsters by administration of 5-fluorouracil (60mg/kg), on days 0, 5, and 10 of the study. The cheek pouch was scratched with a sterile needle on days 1 and 2. On days 12-17, H. perforatum extract topical gel 10%, oral H. perforatum extract (300mg/kg), and gel base groups were treated and then compared with a control group. Weights and blood samples were evaluated, biopsies from buccal lesions were examined histopathologically, and tissue malondialdehyde (MDA) was measured. Both of the H. perforatum extract treatment groups saw a significant relief in oral mucositis compared to the control and base gel groups; the systemic form was superior to the topical form. H. perforatum extract, administered orally or topically, expedited the healing of chemotherapy-induced oral mucositis in hamsters.

Prevention of arthrofibrosis by monoclonal antibody against vascular endothelial growth factor: a novel use of bevacizumab in rabbits.

BACKGROUND: Prevention of arthrofibrosis by different drugs and surgical techniques is an essential issue in modern orthopedics. HYPOTHESIS: Intra-articular injection of bevacizumab can reduce arthrofibrosis on the rabbit's stifle joint model. MATERIALS AND METHODS: Arthrofibrosis was induced in the right stifle joint of thirty male New Zealand white rabbits by removing the cortical bone of the medial femoral condyle under general anesthesia. The rabbits were randomly divided into three equal groups. The control group received intra-articular injection of saline; the one-injection group received a single dose of bevacizumab (2.5mg/kg), and the two-injection group received two intra-articular injections; the operation day and 14 days later. Forty-five days after surgery, animals were sacrificed. The severity of fibrosis was assessed based on the range of motion of the joint, a macroscopic adhesion score, and histopathologic variables such as the number of fibroblasts and of inflammatory cells, collagenous matrix deposition, synovial hyperplasia, granulation tissue formation, vascular proliferation, and presence of giant cells. RESULTS: Although no statistically significant differences were found between the range of motion (P=0.222) and the macroscopic evaluation (P=0.067) of the control group and the one-injection group, all microscopic variables regarding the prevention of arthrofibrosis were significantly superior in the one-injection group except granulation tissue (P=0.347). Compared to the one-injection group, the two-injection group had better results not only in terms of macroscopic evaluation (P=0.001 for range of motion and 0.012 for visual adhesion score) but also in most of the histopathologic variables especially the number of fibroblasts (P=0.002), vascularity (P=0.028) and collagenous matrix deposition (P=0.039). CONCLUSION: A single intra-articular injection of bevacizumab was effective for prevention of microscopically detected arthrofibrosis in the rabbit. Compared to single injection, two injections of bevacizumab improved the clinical outcome. LEVEL OF EVIDENCE: Level II.

The healing effect of arnebia euchroma in second degree burn wounds in rat as an animal model.

BACKGROUND: Finding more efficient agents with fewer side effects for treatment of burns has always been a concern for researchers. Silver sulfadiazine (SSD), apparently due to its antimicrobial effect, is still one of the most common prescribed agents. Previous studies suggested that Arnebia euchroma (AE) has shown antimicrobial and anti-inflammatory activities. This study investigates the healing effect of AE extract in comparison with SSD in second degree burn wounds. METHODS: Fort eight female Wistar rats (220±20 g) were divided into four groups. Standard second degree burn wounds were induced on the back of their necks. One group was treated with SSD; two groups were treated with AE cream at concentrations of 10% (AE10) and 20% (AE20) and the control group which received no treatment. The duration of treatment was 28 days. RESULTS: This study revealed that AE and SSD noticeably improved re-epithelization, fibroblasts proliferation, and collagen bundle synthesis and had a noticeable anti-inflammatory effect compared with the control group. CONCLUSION: Results of the present study revealed that Arnebia euchroma herbal extract was an effective treatment for second degree burn wounds when compared with SSD.

Thioacetamide-induced acute hepatic encephalopathy in rat: behavioral, biochemical and histological changes.

BACKGROUND: As a serious neuropsychiatric disease, hepatic encephalopathy (HE) is a clinical condition with several types regarding chronicity and clinical diversity that can develop as a complication of both acute and chronic liver failure. This study evaluates changes in thioacetamide (TAA)-induced acute hepatic encephalopathy (AHE) in rat as an animal model. METHODS: Both genders of C57BL6, BALB/C mice and Sprague Dawley rats; (10 animals in each group) were compared for induction of AHE to clarify which animal and gender were appropriate. The animals (10 male rats in each group) were categorized in 4 groups according to the dose of the TAA administered (200, 300 and 400 mg/kg of TAA at 24 h intervals for 4 days). A control group was treated with solvent of TAA which was water (5 ml/kg/day). The behavioral, biochemical markers of hepatic failure and histological aspects of thioacetamide (TAA) induced AHE and the correlation between the clinical severity and liver failure biomarkers were evaluated. RESULTS: Rat was shown to be an animal model of choice for AHE while the optimum dosage of TAA to induce AHE was 300 mg/kg/day at 24 h intervals for 4 days. The behavioral score was partially correlated with the rising of some biomarkers and pathological findings. CONCLUSION: Rat can be introduced as the animal of choice for AHE to study the pathophysiology, pharmacology and the survival rate of disease in liver transplant patients.

Differentiation of adipose-derived stem cells into ear auricle cartilage in rabbits.

BACKGROUND: Adipose-derived stem cells have been reported as a novel candidate for the repair of cartilage injuries in vivo. METHODS: In order to assess their differentiation ability, adipose-derived stem cells isolated from rabbit fat tissue were injected into the midportion of a surgically created rabbit ear auricle cartilage defect. After several months, the auricles were resected, histopathologically assessed and compared with a control group. RESULTS: Histopathological examination of auricles removed three, four and five months after injection showed islands of new cartilage formation at the site of the surgically induced defect. Six months after injection, we observed well-formed, mature cartilaginous plates that completely filled the defect in the native cartilage. In the control group, there was no significant growth of new cartilage. CONCLUSION: The results of this study suggest the great potential of adipose-derived stem cells to repair damaged cartilage tissue in vivo.

The effect of calendula officinalis in therapy of acetic Acid induced ulcerative colitis in dog as an animal model.

BACKGROUND: In patients with ulcerative colitis (UC), the repeated cycle of injury and repair of intestinal mucosa has been reported to increase the risk of colon cancer. So, a safe and efficient therapy is required for the treatment and prophylaxis for the disease.This study aims to investigate the efficacy of Calendula officinalis extract in treatment of experimentally induced ulcerative colitis in dog animal model. METHODS: During fall 2010, 10 out-bred female German dogs (1-2 years old; weighs of 20-25 kg) were enrolled. Ulcerative colitis was induced with 6% acetic acid as enema and method of treatment was retrograde (via enema) too by C. officinalis. RESULTS: Loose stools, diarrhea, gross bleeding and loss of body weight happened after administration of acetic acid and crypt damage, loss of epithelium, infiltration of inflammatory cells and depletion of goblet cells were noticed histologically. C. officinalis could successfully resolve the damages of UC. CONCLUSION: Treatment with C. officinalis can broaden the current therapy options for UC.

The healing effect of bioglue in articular cartilage defect of femoral condyle in experimental rabbit model.

BACKGROUND: The full-thickness articular cartilage defects of knee have a poor healing capacity that may progress to osteoarthritis and need a knee replacement. This study determines the healing effect of bioglue in fullthickness articular cartilage defect of femoral condyle in rabbit. METHODS: Forty-eight male rabbits were randomly divided into four equal groups. In group A, 4 mm articular cartilage defects were created in the right and left medial femoral condyles. Then a graft from xiphoid cartilage was transferred into the defect together with a designed bioglue and the knees were closed. In group B, an articular cartilage defect was created identical to group A, but the defect size was 6 mm. In group C, 4 and 6 mm articular cartilage defects were created in the right and left medial femoral condyles respectively. The graft was transferred into the defect and the knees were stitched. In group D, articular cartilage defects were created similar to group C, just filled with bioglue and closed. The rabbits were euthanized and subgroups were defined as A1, B1, C1 and D1 after 30 days and A2, B2, C2 and D2 after 60 days. The cartilages were macroscopically and histologically investigated for any changes. RESULTS: Microscopic and macroscopic investigations showed that bioglue had a significant healing effect in the femoral condyle. CONCLUSION: Addition of bioglue can effectively promote the healing of articular cartilage defects.

Safety of topical methimazole for the treatment of melasma. Transdermal absorption, the effect on thyroid function and cutaneous adverse effects.

Methimazole is an oral antithyroid compound that exhibits a skin-depigmenting effect when used topically. However, the effect of topical methimazole on thyroid function has not been reported. This study was aimed at assessing the safety of topical methimazole used to treat pigmented lesions, without affecting thyroid hormones due to systemic delivery. The pharmacokinetics of methimazole, either applied in the form of a 5% topical formulation to facial skin or taken orally in the form of a 5-mg tablet by 6 volunteers, were determined. In addition, the effect of long-term topical applications of 5% methimazole on the function of the thyroid gland in 20 patients with epidermal melasma was determined following 6 weeks of once-daily application. Cutaneous adverse effects of topical methimazole were determined. From 15 min up to 24 h after application, methimazole was undetectable in the serum of the individuals receiving single topical methimazole dosing. Methimazole, however, was detected in serum after 15 min of oral administration and remained detectable in serum up to 24 h after administration. Long-term topical methimazole applications in melasma patients did not induce any significant changes in serum TSH, free thyroxine and free triiodothyronine levels. Topical methimazole was well tolerated by the patients and did not induce any significant cutaneous side effects. Present data together with the previously shown non-cytotoxic and non-mutagenic characteristics of methimazole indicate that this agent could be considered as a safe skin-depigmenting compound for topical treatment of skin hyperpigmentary disorders in humans.

Comparison of early outcome and histologic findings of enteric drainage with bladder drainage in pancreas transplantation of dogs.

BACKGROUND: The clinical and pathological findings of enteric-drained (ED) versus bladder-drained (BD) pancreas transplantation are still controversial. In this study, we compared early outcome and histological findings of these 2 methods. METHODS: In an experimental animal model, after diabetization, 16 dogs were randomly divided into 2 groups. In the first group, the pancreas was transplanted with enteric drainage, and in the second group, with bladder drainage. We evaluated early clinical and pathological outcomes. RESULTS: The mean survival time was 11.25 +/- 5.0 (range, 5-20) days for group 1 and 13.6 +/- 7.2 (range, 3-23) days for group 2 (P>.05). Fasting blood sugar values (FBS) before transplantation were 279 +/- 26.8 mg/dL versus 278 +/- 41.6 mg/dL, respectively (P>.05). Two weeks postoperative serum FBS had decreased to 84.9 +/- 2.9 versus 84.2 +/- 0.98, respectively (P>.05). Serum amylase in the BD and ED groups were 378.5 +/- 328 versus 422.6 +/- 54.7 mg/dL, respectively (P>.05). Early leakage was not observed in dogs with BD, whereas it was 37.5% among dogs with ED (P<.05). Clinical and pathological evidences of pancreatic necrosis occurred in 37.5% of dogs with BD versus 62.5% of dogs with ED (P>.05). DISCUSSION: Although the early outcomes of these drainage methods (ED vs BD) were statistically similar more dogs with ED experienced early complications than with BD.

Urethral reconstruction using autologous and everted vein graft: an experimental study.

Urethral reconstruction is one of the problematic issues in pediatric surgery. To evaluate the efficacy of vein graft for urethral reconstruction in rabbits, about 3 cm of distal urethra was excised under microscopic magnification. In groups A, B, and D, the urethra was replaced with the internal jugular vein. In group B, before performing anastomosis, vein grafts were everted. In group C (control group) after removing the urethra, a catheter was inserted without substituting the urethra and then fixed. Groups A, B, and C were kept for 3 months. Group D was divided into five subgroups each consists of two rabbits, which were killed at days 7, 10, 14, 22, and 30 for evolutionary histopathological studies. Gross evaluation, retrograde urethrography, and histopathological studies were also performed in other groups. Retrograde urethrography and gross evaluation revealed no sign of stricture and fistula formation in six and eight rabbits in groups A and B, respectively. However, those complications were observed in all the rabbits in group C. The grafted part of the neourethra was epithelialized with uroepithelium in all rabbits in group A (vein graft) and group B (everted vein graft) but only partial epithelialization was observed in three rabbits of group C. Severe fibrosis with stricture formation was developed in six rabbits in the control group. In group D, epithelialization gradually replaced necrosis and inflammation, within 1 month. This study showed that vein, everted or not, can be used as a substitute for urethra. It also suggests that new epithelialization might be formed from ingrowing of the uroepithelium from the proximal part.

Biologic resurfacing of the patella with quadriceps tendon flap: a rabbit study.

In this experimental study, 10 rabbits underwent arthrotomy with exposure of the patellar bone (group A), 10 rabbits underwent arthrotomy of the right knee without touching the patella (group B), and 10 rabbits comprised the control group (group C), which was included only for evaluation of functional scoring activities. A 2-mm thick flap of quadriceps tendon reflected downward to cover the patellar bone denuded of cartilage, which resulted in formation of hyaline cartilage in 87% of cases in group A and 89% in group B, incomplete differentiation of the mesenchymal tissue in 7% in group A and 9% in group B, and fibrous tissue or bone formation in 6% in group A and 2% in group B. In group A, 22% of formed cartilage had a regular surface, 22% had superficial horizontal lamination, 44% had fissuring, and 12% showed severe disruption. In group B, these values were 56%, 33%, 11%, and 0%, respectively. In group A, normal cellularity was noted in 33% of cases, slight hypocellularity in 67%, and no moderate hypocellularity. In group B, these values were 56%, 33%, and 11%, respectively. This procedure should be considered in young patients with loss of articular cartilage for whom other procedures or patellectomy are unsuitable solutions.