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OBJETIVO: Analisar, por meio da histomorfometria, o efeito do alendronato de sódio sobre o trabeculado ósseo de ratos, quando administrado simultaneamente com imobilização gessada. MÉTODOS: Foram utilizados quatro grupos com cinco fêmeas de ratos Wistar: 1) imobilizado; 2) não imobilizado + alendronato; 3) imobilizado + alendronato; e 4) controle. A imobilização foi feita com gesso pelvipodálico aplicado até o membro posterior direito e o alendronato foi administrado em doses semanais. O período de observação foi de 28 dias e realizada histomorfometria da metáfise proximal da tíbia, com análise do número de trabéculas, volume ósseo, espessura trabecular e separação trabecular. RESULTADOS: O grupo imobilizado apresentou volume ósseo menor que os demais grupos. Os animais que receberam alendronato semanal, tanto imobilizados, quanto não imobilizados, apresentaram volume ósseo maior que o controle. A espessura trabecular no grupo imobilizado foi menor do que nos grupos controle e não imobilizado que recebeu alendronato, mas não apresentou diferença significativa em relação ao imobilizado com alendronato. O grupo imobilizado apresentou separação trabecular maior que os demais grupos. Os grupos não imobilizado, sem imobilização que recebeu alendronato e imobilizado que recebeu alendronato apresentaram aumento no número de trabéculas em relação ao grupo imobilizado. CONCLUSÃO: A imobilização empregada efetivamente levou à osteopenia, verificada pela diminuição de todos os principais parâmetros histomorfométricos estudados. Estas alterações foram prevenidas pela administração concomitante de alendronato sódico, exceto com relação à espessura trabecular. O alendronato de sódio foi capaz de aumentar os parâmetros morfométricos, mesmo em animais não imobilizados.

OBJECTIVE: Using histomorphometric means to analyze the effect of alendronate sodium on the bone trabeculate of rats administered concomitantly with cast immobilization. METHODS: Female Wistar rats were distributed in four groups with five animals each: 1) cast-immobilized; 2) no immobilization + alendronate; 3) cast-immobilized + alendronate; and 4) control. Immobilization was done with pelvipodalic cast applied till the right hind limb and alendronate was administered in weekly doses. The observation period was 28 days and histomorphometric evaluations were performed in the proximal tibial metaphysis, analyzing the number of trabeculae, bone volume, trabecular thickness, and trabecular separation. RESULTS: The immobilized group presented less bone volume than the other groups. The animals receiving alendronate every week, whether or not immobilized, presented a greater bone volume than the control group. Trabecular thickness in the immobilized group was less than in the control and in the non-immobilized groups that received alendronate, but had no significant difference when compared to the immobilized with alendronate group. The immobilized group presented greater trabecular separation than the other groups. In the non-immobilized groups, the non-immobilized group that received alendronate and the immobilized group that received alendronate presented an increased number of trabeculae when compared to the immobilized group. CONCLUSION: The immobilization used led to osteopenia, as confirmed by the decrease in all of the main histomorphometric parameters studied. Such changes were prevented with the concomitant administration of alendronate sodium, exception being made to the trabecular thickness. Alendronate sodium was able to increase morphometric parameters, even in non-immobilized animals.

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The aim of the present study was to examine the efficacy and potential side effects of repeated doses of oral sucrose for pain relief during procedures in NICU. Thirty-three preterm neonates were randomly allocated in blind fashion into two groups, the sucrose group (SG=17) and the control group (CG=16). The responses of neonates to pain and distress were assessed during blood collection on four consecutive assessment (ass.) days. For the first assessment, the neonates did not receive any solution before the blood collection procedure. During the next three days, the SG received oral sucrose (25%; 0.5 ml/kg) and the CG received sterile water, 2 min before each minor acute painful procedure. The neonates were evaluated during blood collection each morning. The assessment was divided into five phases: Baseline (BL), Antisepsis (A), Puncture (P), Dressing (D), and Recovery (R). The neonates' facial activity (NFCS), behavioral state, and heart rate were evaluated. The data analysis used cut-off scores for painful and distressful responses. No side effects of using sucrose were detected. There were significantly fewer SG neonates with facial actions signaling pain than CG neonates in P (ass.2) and in A (ass.3). We found significantly fewer SG neonates in the awake state than CG neonates in P (ass.2 and ass.4). There were significantly fewer SG neonates crying during A (ass.2), P (ass.2 and ass.4), and D (ass.3). There was no statistical difference between-groups for physiological response. The efficacy of sucrose was maintained for pain relief in preterm neonates with no side effects.

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RESUMO

In order to investigate the effects of monoaminergic mechanisms of the dorsal raphe nucleus on the elaboration and control of sweet-substance-induced antinociception, male albino Wistar rats weighing 180-200 g received sucrose solution (250 g/L) for 14 days as their only source of liquid. After the chronic consumption of sucrose solution, each animal was pretreated with unilateral microinjection of methiothepin mesylate (5.0 microg/0.2 microL), or methysergide maleate (5.0 microg/0.2 microL) in the dorsal raphe nucleus. Each rat consumed an average of 15.6g sucrose/day. Their tail withdrawal latencies in the tail-flick test were measured immediately before and after this treatment. An analgesia index was calculated from the withdrawal latencies before and after the pharmacological treatment. The blockade of serotonergic receptor in the dorsal raphe nucleus with methysergide after the chronic intake of sucrose decreased the sweet-induced antinociception. However, microinjections of methiothepin in the dorsal raphe nucleus did not cause a similar effect on the tail-flick latencies after the chronic intake of sucrose solution, increasing the sweet-substance-induced analgesia. These results indicate the involvement of serotonin as a neurotransmitter in the sucrose-produced antinociception. Considering that the blockade of pre-synaptic serotonergic receptors of the neural networks of the dorsal raphe nucleus with methiothepin did not decrease the sweet-substance-induced antinociception, and the central blockade of post-synaptic serotonergic receptors decreased the sucrose-induced analgesia, the modulation of the release of serotonin in the neural substrate of the dorsal raphe nucleus seems to be crucial for the organization of this interesting antinociceptive process.

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