The effect of the carotenoid bixin and annatto seeds on hematological markers and nephrotoxicity in rats subjected to chronic treatment with cisplatin

ABSTRACT This study assessed the protective effect of the carotenoid bixin and annatto seeds against possible nephrotoxicity induced with a single peritoneal administration of pharmacological cisplatin in male Wistar rats. After 48 h, the blood cell differential count showed a significant reduction in neutrophil counts in rats that received a diet rich in bixin when compared to the group that received only cisplatin. The use of cisplatin led to an increase in kidney weight. The carotenoid bixin attenuated renal injury, characterized by increased polymorphonuclear infiltration. No protective effect was observed with respect to Annatto. These results demonstrate the role of toxic cisplatin and suggest that bixin affords a protective effect against cisplatin-induced nephrotoxicity in adult Wistar rats.

Análise morfométrica do nervo isquiático de ratos Wistar adultos submetidos à compressão crônica através de um clipe cirúrgico / Morphometric analysis of the sciatic nerve of Wistar rats submitted to chronic compression through surgical clip

Introdução: Hiperidrose é uma condição idiopática caracterizada por sudorese excessiva generalizada ou restrita a extremidades. O tratamento definitivo e com menor morbidade é a simpatectomia videotoracoscópica. O bloqueio da cadeia simpática com clipe possibilitaria a reversão da cirurgia para pacientes que sofrem de hiperidrose compensatória pós-operatória ­ complicação mais problemática. Como objetivo, este trabalho visa analisar a arquitetura ultraestrutural e morfométrica do nervo isquiático de ratos Wistar machos adultos submetidos à compressão crônica através de um clipe cirúrgico. Os objetivos são identificar se há alteração nervosa com o clipamento e se existe tempo para promover o retorno às atividades neuronais pós-retirada do clipe. Pode-se, portanto, verificar se o clipamento é eficaz como forma de tratamento para hiperidrose, com a vantagem de ser um procedimento reversível. Métodos: Foram selecionados 30 ratos Wistar machos separados em 3 grupos ­ 1, 2 e 3 ­ com n=10, com a retirada do clipe em 1, 2 e 4 semanas, respectivamente. Cada grupo foi dividido em A e B com n=5. Todos os ratos do grupo A eram sacrificados no momento da retirada do clipe e, no B, uma semana após a retirada do clipe. Resultados: O estudo mostrou que, em cada um dos grupos, houve nervos normais e com degeneração, independentemente da retirada do clipe ou de sua manutenção. Conclusão: Simpatectomia com clipe parece não ser um bom método para o tratamento da hiperidrose. O efeito da simpatectomia com clipe e sua remoção devem ser melhor observados em grandes estudos (AU)

Introduction: Hyperhidrosis is an idiopathic condition characterized by excessive sweating that may be generalized or restricted to specific parts of the body. The definitive treatment with less morbidity is endoscopic thoracic sympathectomy. Blockade of the sympathetic chain with a clip enables reversal of surgery for patients suffering from postoperative compensatory sweating ­ the most problematic complication. This work was designed to assess the ultrastructural and morphometric architecture of the sciatic nerve of adult male Wistar rats subjected to chronic compression via surgical clip. The aims were to determine if there are changes to nerve from clipping and if there is time to restore neuronal activity after removal of the clip. One can thus check if clipping is an effective treatment for hyperhidrosis, with the advantage of being a reversible procedure. Methods: Thirty male Wistar rats were selected and divided into 3 groups of ten rats each, with removal of the clip at weeks 1, 2 and 4, respectively. Each group was divided into A and B with n = 5. Rats in group A were sacrificed at the time of clip withdrawal and rats in group B were sacrifi ced one week after clip withdrawal. Results: The study showed that, in each of the groups, there were normal and degenerated nerves regardless of clip removal or maintenance. Conclusion: Sympathectomy with clip does not seem to be a good method for the treatment of hyperhidrosis. The effect of sympathectomy with clip and its removal should be further investigated in larger studies (AU)

Plantar thermography is useful in the early diagnosis of diabetic neuropathy

OBJECTIVES: This study evaluated plantar thermography sensitivity and specificity in diagnosing diabetic polyneuropathy using cardiac tests (heart rate variability) as a reference standard because autonomic small fibers are affected first by this disease. METHODS: Seventy-nine individuals between the ages of 19 and 79 years old (28 males) were evaluated and divided into three groups: control (n = 37), pre-diabetics (n = 13) and type 2 diabetics (n = 29). The plantar images were recorded at baseline and then minutes after a provocative maneuver (Cold Stress Test) using an infrared camera that is appropriate for clinical use. Two thermographic variables were studied: the thermal recovery index and the interdigital anisothermal technique. Heart rate variability was measured in a seven-test battery that included three spectral indexes (in the frequency domain) and four Ewing tests (the Valsalva maneuver, the orthostatic test, a deep breathing test, and the orthostatic hypotension test). Other classically recommended tests were applied, including electromyography (EMG), Michigan inventory, and a clinical interview that included a neurological physical examination. RESULTS: Among the diabetic patients, the interdigital anisothermal technique alone performed better than the thermal recovery index alone, with a better sensitivity (81.3%) and specificity (46.2%). For the pre-diabetic patients, the three tests performed equally well. None of the control subjects displayed abnormal interdigital anisothermal readouts or thermal recovery indices, which precluded the sensitivity estimation in this sample of subjects. However, the specificity (70.6%) was higher in this group. CONCLUSION: In this study, plantar thermography, which predominately considers the small and autonomic fibers that are commonly associated with a sub-clinical condition, proved useful in diagnosing diabetic neuropathy early. The interdigital anisothermal test, when used alone, performed best.

Exercise alleviates hypoalgesia and increases the level of calcitonin gene-related peptide in the dorsal horn of the spinal cord of diabetic rats

OBJECTIVE: The aim of this study was to evaluate the effects of treadmill training on nociceptive sensitivity and immunoreactivity to calcitonin gene-related peptide in the dorsal horn of the spinal cord of diabetic rats. METHODS: Male Wistar rats were divided into three groups: control, diabetic and trained diabetic. Treadmill training was performed for 8 weeks. The blood glucose concentrations and body weight were evaluated 48 h after diabetes induction and every 30 days thereafter. The nociceptive sensitivity was evaluated using the tail-flick apparatus. The animals were then transcardially perfused, and the spinal cords were post-fixed, cryoprotected and sectioned in a cryostat. Immunohistochemistry for calcitonin gene-related peptide analysis was performed on the dorsal horn of the spinal cord. RESULTS: The nociceptive sensitivity analysis revealed that, compared with the control and trained diabetic animals, the latency to tail deflection on the apparatus was longer for the diabetic animals. Optical densitometry demonstrated decreased calcitonin gene-related peptide immunoreactivity in the dorsal horn of the spinal cord in diabetic animals, which was reversed by treadmill training. CONCLUSION: We concluded that treadmill training can alleviate nociceptive hypoalgesia and reverse decreased calcitonin gene-related peptide immunoreactivity in the dorsal horn of the spinal cord of diabetic animals without pharmacological treatment.

Thermographic evaluation of hind paw skin temperature and functional recovery of locomotion after sciatic nerve crush in rats

INTRODUCTION: Peripheral nerves are often damaged by direct mechanical injury, diseases, and tumors. The peripheral nerve injuries that result from these conditions can lead to a partial or complete loss of motor, sensory, and autonomic functions, which in turn are related to changes in skin temperature, in the involved segments of the body. The aim of this study was to evaluate the changes in hind paw skin temperature after sciatic nerve crush in rats in an attempt to determine whether changes in skin temperature correlate with the functional recovery of locomotion. METHODS: Wistar rats were divided into three groups: control (n = 7), sham (n = 25), and crush (n = 25). All groups were subjected to thermographic, functional, and histological assessments. RESULTS: ΔT in the crush group was different from the control and sham groups at the 1st, 3rd and 7rd postoperative days (p<0.05). The functional recovery from the crush group returned to normal values between the 3rd and 4th week post-injury, and morphological analysis of the nerve revealed incomplete regeneration at the 4th week after injury. DISCUSSION: This study is the first demonstration that sciatic nerve crush in rats induces an increase in hind paw skin temperature and that skin temperature changes do not correlate closely with functional recovery.

Beneficial effects of treadmill training in experimental diabetic nerve regeneration

OBJECTIVES: We investigated the effects of treadmill training (10 weeks) on hindlimb motor function and nerve morphometric parameters in diabetic rats submitted to sciatic nerve crush. MATERIALS AND METHOD: Wistar rats (n = 64) were divided into the following groups: non-diabetic; trained non-diabetic; non-diabetic with sciatic nerve crush; trained non-diabetic with sciatic nerve crush; diabetic; trained diabetic; diabetic with sciatic nerve crush or trained diabetic with sciatic nerve crush. Diabetes was induced by streptozotocin injection (50 mg/kg, iv). Hindlimb motor function was evaluated weekly by assessing sciatic functional indices, and the proximal and distal portions of the sciatic nerve were used for morphometric analysis. RESULTS: At 13 weeks post-injury, the distal nerve portion of all injured groups and the proximal nerve portion of the diabetic with sciatic nerve crush group presented altered morphometric parameters such as decreased myelinated fiber diameter (~7.4 + 0.3μm vs ~4.8 + 0.2μm), axonal diameter (~5 + 0.2μm vs ~3.5 + 0.1μm) and myelin sheath thickness (~1.2 + 0.07μm vs ~0.65 + 0.07μm) and an increase in the percentage of area occupied by endoneurium (~28 + 3 percent vs ~60 + 3 percent). In addition, in the non-diabetic with sciatic nerve crush group the proximal nerve portion showed a decreased myelinated fiber diameter (7.4+0.3μm vs 5.8 + 0.3μm) and myelin sheath thickness (1.29 + 0.08μm vs 0.92 + 0.08μm). The non-diabetic with sciatic nerve crush, trained non-diabetic with sciatic nerve crush, diabetic with sciatic nerve crush and trained diabetic with sciatic nerve crush groups showed normal sciatic functional index from the 4th,4th,9th and 7th week post-injury, respectively. Morphometric alterations in the proximal nerve portion of the diabetic with sciatic nerve crush and non-diabetic with sciatic nerve crush groups were either prevented or reverted to values similar to the non-diabetic group by treadmill training. CONCLUSION: Diabetic condition promoted delay in sciatic nerve regeneration. Treadmill training is able to accelerate hindlimb motor function recovery in diabetic injured rats and prevent or revert morphometric alterations in proximal nerve portions in non-diabetic and diabetic injured rats.