Methods for obtaining the enriched fraction of ram seminal vesicle proteins (RSVP14)

The objective of the present study was to develop a methodology to obtain the enriched fraction of ram seminal vesicle protein 14 (RSVP14). The study was developed using Morada Nova rams, from which semen samples were collected weekly. Seminal plasma proteins were precipitated with cold ethanol, and then 6.15 mg/mL of total proteins were subjected to liquid gelatin affinity chromatography using a GelatinSepharose matrix coupled to an automated chromatographic system. Proteins were eluted into four fractions (A, B, C, and D), in which A and B contained non-gelatin-binding proteins, and C and D fractions contained gelatin-binding proteins. Gels were analyzed by Quantity One software, in which five protein bands were detected in fraction D, with molecular weights between 12 and 30 kDa. The gelatin-binding proteins (fraction D) were loaded into a HiTrap™ Heparin HP affinity column. Two chromatographic fractions were separated (D1 and D2), in which D1 contained non-heparin-binding proteins, and D2 contained heparin-binding proteins. Proteins from the last two peaks were subjected to 12.5% SDS-PAGE and Western Blot. Two bands with molecular weight of 14 and 24 kDa, contained in fraction D1, were excised from gel and subjected to tandem mass spectrometry, identifying the proteins RSVP14 and RSVP24. Thus, the chromatographic methods of the present study are efficient to capture the enriched fraction of RSVP14.(AU)

Mini-Percoll technique induces similar capacitation features in domestic ruminant frozen-thawed spermatozoa regardless of the presence of heparin

Background: Sperm capacitation is a process consists of a series of functional, biochemical, and biophysical modificationsthat render the ejaculated sperm competent for oocyte fertilization. Secreted by the female reproductive tract epithelium,heparin promotes capacitation by binding to and removing seminal plasma proteins, which are adsorbed to the sperm PMand would inhibit capacitation. There is substantial evidence that cryopreservation promotes capacitation-like changes inbull, ram and buck sperm. Our general hypotheses were: (a) cryopreserved ram sperm suffer capacitation more quicklythan buck and bull sperm under the same conditions; (b) the capacitation status of ruminant cryopreserved sperm is similarwhether or not heparin is present after the mini-Percoll technique; and (c) ruminant frozen-thawed sperm selected by miniPercoll and incubated within media without heparin supplementation is not impaired in terms of capacitation status andsperm agglutination. This study aimed to compare sperm parameters of ovine, caprine, and bovine frozen-thawed spermafter mini-Percoll processing followed by incubation with or without heparin supplementation.Materials, Methods & Results: Commercial semen of all species were used. Sperm samples were selected by mini-Percolland supplemented (or not) with heparin within an incubation medium for 18 h. Sperm kinematics (CASA system analyzes),capacitation status (CTC staining) and sperm agglutination were evaluated after thawing, mini-Percoll, 1.5 h, 3 h, 6 h and18 h. In comparison with post-thawing analysis, ovine species demonstrated a reduction (P < 0.05) in most of the spermmotility parameters after mini-Percoll. Conversely, ovine samples presented...

Mini-Percoll technique induces similar capacitation features in domestic ruminant frozen-thawed spermatozoa regardless of the presence of heparin

Background: Sperm capacitation is a process consists of a series of functional, biochemical, and biophysical modificationsthat render the ejaculated sperm competent for oocyte fertilization. Secreted by the female reproductive tract epithelium,heparin promotes capacitation by binding to and removing seminal plasma proteins, which are adsorbed to the sperm PMand would inhibit capacitation. There is substantial evidence that cryopreservation promotes capacitation-like changes inbull, ram and buck sperm. Our general hypotheses were: (a) cryopreserved ram sperm suffer capacitation more quicklythan buck and bull sperm under the same conditions; (b) the capacitation status of ruminant cryopreserved sperm is similarwhether or not heparin is present after the mini-Percoll technique; and (c) ruminant frozen-thawed sperm selected by miniPercoll and incubated within media without heparin supplementation is not impaired in terms of capacitation status andsperm agglutination. This study aimed to compare sperm parameters of ovine, caprine, and bovine frozen-thawed spermafter mini-Percoll processing followed by incubation with or without heparin supplementation.Materials, Methods & Results: Commercial semen of all species were used. Sperm samples were selected by mini-Percolland supplemented (or not) with heparin within an incubation medium for 18 h. Sperm kinematics (CASA system analyzes),capacitation status (CTC staining) and sperm agglutination were evaluated after thawing, mini-Percoll, 1.5 h, 3 h, 6 h and18 h. In comparison with post-thawing analysis, ovine species demonstrated a reduction (P < 0.05) in most of the spermmotility parameters after mini-Percoll. Conversely, ovine samples presented...(AU)

Proteins of the canine seminal plasma / Proteínas do plasma seminal canino

Studies have been performed to identify the proteins present in canine seminal plasma (SP) and relate them to sperm quality as well as to discover molecular markers of reproductive tract diseases. There is evidence that heparin-binding proteins, zinc-binding proteins, and lactoferrin as well as the matrix metalloproteinase, superoxide dismutase, catalase, and glutathione peroxidase enzymes are associated with canine sperm quality. Other studies indicate that prolactin and enzymes like arginine esterase, acid phosphatase, and alkaline phosphatase could be successfully used as biomarkers of reproductive disorders. Thus, the present literature review aims to address aspects related to proteins of the canine SP, their influence on fertility, and their importance as biomarkers of reproductive disorders.(AU)

Pesquisas têm sido realizadas para identificar as proteínas presentes no plasma seminal canino, com o intuito de relacioná-las com a qualidade espermática, bem como buscar por marcadores moleculares de patologias do trato reprodutivo. Há evidências de que as proteínas ligadoras de heparina, ligadoras de zinco, a lactoferrina, bem como as enzimas matrix metalloproteinase, superoxide dismutase, catalase e a glutationa peroxidase estão relacionadas com a qualidade seminal canina. Outras pesquisas indicam que a prolactina, e as enzimas arginina esterase, fosfatase ácida e fosfatase alcalina poderiam ser utilizadas com sucesso como biomarcadores de doenças reprodutivas. Assim, esta revisão de literatura objetiva abordar aspectos relacionados às proteínas do plasma seminal canino, suas influências sobre a fertilidade, e sua importância como biomarcadores de doenças reprodutivas.(AU)

Proteínas do plasma seminal canino: revisão / Protein patterns of canine seminal plasma: review

Nas últimas décadas, o crescente interesse pela cinofilia motivou o crescimento de uma atividadecomercial lucrativa. Assim, há um interesse em aumentar a performance reprodutiva por meio de biotécnicas dareprodução, como a criopreservação de gametas e a inseminação artificial. A identificação de proteínas presentesno plasma seminal canino dá início a novas discussões sobre o uso de proteínas em aditivos que melhorem aviabilidade espermática e possam ser usados como método contraceptivo em cadelas. Dessa forma, este trabalhoobjetivou descrever as proteínas do plasma seminal canino verificadas na literatura científica, como alactoferrina, a arginina esterase, as proteínas ligadoras de heparina, a osteopontina e as proteínas ligadoras dezinco, assim como relacioná-las com suas respectivas funções diante da esfera reprodutiva.(AU)

In the past few years, the interesting in dogs has provided an increase of this commercial activity. Thus,there is an interest in the increase of reproductive performance using biotechnology such as semencryopreservation and artificial insemination. The identification of proteins present in seminal plasma canineamazed initiates further discussion on the use of protein additives that improve sperm viability and it can used ascontraception in female dogs. Thus, this study aimed to describe the canine seminal plasma proteins, describedin the scientific literature, such as lactoferrin, arginine esterase, the heparin-binding proteins, osteopontin andzinc binding proteins, as well as relate them to their respective functions on the reproductive sphere.(AU)

Proteínas do plasma seminal canino: revisão / Protein patterns of canine seminal plasma: review

Nas últimas décadas, o crescente interesse pela cinofilia motivou o crescimento de uma atividadecomercial lucrativa. Assim, há um interesse em aumentar a performance reprodutiva por meio de biotécnicas dareprodução, como a criopreservação de gametas e a inseminação artificial. A identificação de proteínas presentesno plasma seminal canino dá início a novas discussões sobre o uso de proteínas em aditivos que melhorem aviabilidade espermática e possam ser usados como método contraceptivo em cadelas. Dessa forma, este trabalhoobjetivou descrever as proteínas do plasma seminal canino verificadas na literatura científica, como alactoferrina, a arginina esterase, as proteínas ligadoras de heparina, a osteopontina e as proteínas ligadoras dezinco, assim como relacioná-las com suas respectivas funções diante da esfera reprodutiva.

In the past few years, the interesting in dogs has provided an increase of this commercial activity. Thus,there is an interest in the increase of reproductive performance using biotechnology such as semencryopreservation and artificial insemination. The identification of proteins present in seminal plasma canineamazed initiates further discussion on the use of protein additives that improve sperm viability and it can used ascontraception in female dogs. Thus, this study aimed to describe the canine seminal plasma proteins, describedin the scientific literature, such as lactoferrin, arginine esterase, the heparin-binding proteins, osteopontin andzinc binding proteins, as well as relate them to their respective functions on the reproductive sphere.

Identificação de proteínas do plasma seminal de touros da raça Gir / Identification of seminal plasma proteins in Gir bulls

Estudou-se o perfil de proteínas totais (PLB) e proteínas ligadoras de heparina (PLH) do plasma seminal de touros da raça Gir e suas associações com parâmetros andrológicos e fertilidade in vitro. A concentração da PLB variou de 4,1 a 167,9 mg/mL e da PLH entre 0,02096 e 0,19025 (%). O perfil cromatográfico apresentou nove picos de afinidade para PLB e cinco picos para PLH. As associações significativas foram: PLB x taxa de blastocistos, PLH do pico 1 x taxa de blastocistos, PLH do pico 5 x taxa de clivagem e blastocistos. Nenhuma proteína estudada apresentou associação com parâmetros andrológicos. (AU)

It was studied the seminal plasma total protein (TP) and heparin binding protein (PLH) profiles of Gyr bulls and their associations with andrological parameters and in vitro fertility. Total protein concentration varied between 4,1 a 167,9 mg/ml and heparin binding protein 0,02096 to 0,19025 (%). Chromatographic profile of TP presented nine peaks. PLH presented five affinity peaks. Associations were for: total proteins x blastocysts rate, peak 1 heparin binding proteins x blastocysts rate, peak 5 heparin binding protein x cleavage rate and blastocysts rate. However no protein showed association with andrological parameters. (AU)

Identificação de proteínas do plasma seminal de touros da raça Gir / Identification of seminal plasma proteins in Gir bulls

Estudou-se o perfil de proteínas totais (PLB) e proteínas ligadoras de heparina (PLH) do plasma seminal de touros da raça Gir e suas associações com parâmetros andrológicos e fertilidade in vitro. A concentração da PLB variou de 4,1 a 167,9 mg/mL e da PLH entre 0,02096 e 0,19025 (%). O perfil cromatográfico apresentou nove picos de afinidade para PLB e cinco picos para PLH. As associações significativas foram: PLB x taxa de blastocistos, PLH do pico 1 x taxa de blastocistos, PLH do pico 5 x taxa de clivagem e blastocistos. Nenhuma proteína estudada apresentou associação com parâmetros andrológicos.

It was studied the seminal plasma total protein (TP) and heparin binding protein (PLH) profiles of Gyr bulls and their associations with andrological parameters and in vitro fertility. Total protein concentration varied between 4,1 a 167,9 mg/ml and heparin binding protein 0,02096 to 0,19025 (%). Chromatographic profile of TP presented nine peaks. PLH presented five affinity peaks. Associations were for: total proteins x blastocysts rate, peak 1 heparin binding proteins x blastocysts rate, peak 5 heparin binding protein x cleavage rate and blastocysts rate. However no protein showed association with andrological parameters.

PURIFICAÇÃO PARCIAL DA BSP5 DO PLASMA SEMINAL BOVINO

O plasma seminal vem sendo objeto de várias pesquisas devido a sua importância na fisiologia espermática, ao qual a análise dos fluidos reprodutivos fornece informações cruciais para a compreensão dos mecanismos que determinam a capacidade fecundante dos gametas masculinos. Objetivou-se no presente estudo indicar um método para purificar a Binder of SPerm 5 (BSP5), proteína de 30 kDa presente no fluido das glândulas vesiculares de touros Bos indicus. O fluido seminal foi extraído das glândulas vesiculares obtidas em abatedouro, e posteriormente, submetido às cromatografias de afinidade à heparina (Hitrap Heparin HP) seguida pela cromatografia de troca iônica (SP Sepharose). Para o monitoramento da purificação, realizou-se SDS-PAGE e para confirmação das proteínas foi realizado western blot com anticorpo específico para BSP5. Baseado no perfil cromatográfico da heparina, foram observados dois picos bem definidos (nHBP e HBP), dos quais o pico referente às proteínas com afinidade pela heparina (HBP) representou percentual de 51,5% de proteínas do fluido das glândulas vesiculares. As HBPs, quando separadas por meio de cromatografia de troca-iônica, apresentaram seis picos agrupados em quatro frações cromatográficas (P1, P2, P3 e P4), dos quais os picos de proteínas ligantes (P3 e P4) totalizou 80,97%. O Western blot com anticorpo anti-BSP5 purificado a partir de anti-soro de coelho, confirmou a presença da banda de 30 kDa no fluido das glândulas vesiculares, no pico com afinidade à heparina e pico 4 da troca iônica. A partir dessa purificação parcial, foi observada que a sequência cromatográfica de afinidade pela heparina seguida de troca catiônica, é eficaz para capturar a BSP5. Contudo, faz-se necessário a ampliação desse método, seguido de confirmações através de sequenciamento recombinante e espectrometria de massas. E a partir dessa purificação é possível a realização de testes funcionais que permitem compreender os mecanismos pelos quais as proteínas BSPs modulam a capacitação espermática, além de incrementar processos biotecnológicos.

Seminal plasma has been the subject of several studies due to its importance in sperm physiology, which analysis of reproductive fluids provides crucial information for understanding the mechanisms that determine the fertile ability of male gametes. The objective of the present study was to indicate a method to purify the Binder of SPerm 5 (BSP5), a 30-kDa protein present in the vesicles gland fluid from Bos indicus bulls. The seminal fluid extracted from seminal vesicles glands was obtained in abattoir, and subsequently subjected to heparin affinity chromatography (Hitrap Heparin HP), followed by ion exchange chromatography (SP Sepharose). For the monitoring of purification, SDS-PAGE was performed and western blotting with BSP5-specific antibody was performed for protein confirmation. Based on heparin-binding proteins, it was observed two well-separated peaks (nHBP and HBP), which heparin-binding proteins (HBP) represented a percentage of 51.5% of seminal vesicle fluid proteins. HBPs, when separated by ion exchange chromatography, showed four peaks (P1, P2, P3 and P4), which the peaks of binding proteins (P3 and P4) represented 80.97%. Western blot with anti-BSP5 antibody purified from rabbit antiserum confirmed the presence of the 30-kDa band in seminal vesicle fluid, HBPs and ion exchange peak 4. From this partial purification, it was observed that heparin followed by ion exchange chromatographies are effective to capture the BSP5. However, it is necessary to extend this method, followed by confirmations through sequencing and mass spectrometry. Moreover, from this purification it is possible to perform functional tests that allow the understanding of the mechanism by which BSP proteins modulate the sperm capacitation, in addition to increasing biotechnological processes.

ESTRATÉGIAS ÔMICAS PARA O ESTUDO DE MARCADORES MOLECULARES DA FERTILIDADE: MAPEAMENTO DAS PROTEÍNAS SEMINAIS COM AFINIDADE À GELATINA E HEPARINA DE ESPÉCIES DOMÉSTICAS E METABOLOMA DOS ESPERMATOZOIDES BOVINOS

A fertilidade animal é um fator que afeta a eficiência reprodutiva nos rebanhos e, consequentemente, causa um forte impacto na economia para a produção de carne e leite. Assim, ferramentas biotecnológicas, como a proteomica e a metabolômica vêm sendo utilizadas e representa um avanço potencial para a escolha de reprodutores de fertilidade comprovada nos rebanhos. Biomoléculas, tais quais as proteínas de ligação à gelatina (PLG) e heparina (PLH) e metabólitos, participam de diversos eventos fisiológicos na célula espermática até a fertilização. Dessa forma, essas biomoléculas seminais podem ser utilizadas como biomarcadores para fertilidade em diversas espécies. Assim, os objetivos do presente trabalho foram (1) identificar o perfil das PLG e PLH no plasma seminal de espécies domésticas e (2) identificar metabólitos espermáticos associados à fertilidade em touros Holstein. Para alcançar o objetivo do estudo 1, o plasma seminal de bovinos, caprinos, ovinos, coelhos, equinos e suínos foram submetido à cromatografia líquida de eficiência rápida (FPLC) e a espectrometria de massas. Adicionalmente, utilizaram-se ferramentas de bioinformática para avaliar os processos fisiológicos os quais essas proteínas estão envolvidas. O total de PLG foram em bovinos (354), caprinos (103), ovinos (51), coelhos (146), equinos (25) e suínos (87). Dentre as PLG mais abundantes, identificaram-se proteínas da família das espermadesinas. O total das PLH foram em bovinos (894), caprinos (789), ovinos (647), coelhos (600), equinos (556) e suínos (86). As PLH com maiores concentrações incluem a bodesina 2, proteína S100, clusterina, PSP-I, PSP-II, dentre outras. As análises in silico mostram que essas moléculas participam, principalmente, dos processos biológicos celulares e possuem função molecular de ligação. Para alcançar o objetivo do estudo 2, identificaram-se através da técnica de CG-ES os metabólitos de espermatozoides de 10 touros com alta (n = 5) e baixa (n = 5) fertilidade. Adicionalmente, foram realizadas análises estatísticas multivariada e univariada através do programa MetaboAnalyst 3.0, para identificar os metabólitos associados a fertilidade. Os resultados mostraram que dentre os 41 diferentes metabólitos identificados nos espermatozoides, os níveis de quatro compostos foram diferentemente significativos e, portanto, podem ser utilizados como biomarcadores moleculares. Esses metabólitos foram aminometano e ácido azeláico (maiores em espermatozoides dos touros de baixa fertilidade) e ácido butírico e uréia (maiores nos espermatozoides dos touros de alta fertilidade). Os resultados da presente pesquisa são significativos porque ajudam a promover a 13 ciência animal básica e as proteínas e metabólitos identificados podem ser usados na biotecnologia reprodutiva para avaliar a qualidade do sêmen e prever a fertilidade de reprodutores.

Animal fertility is a factor that affects reproductive efficiency in herds and has a strong impact on the economy for meat and milk production. Thus, biotechnological tools such as a proteomic and metabolomic have been used and represent a potent tool for a choice of breeding with proven fertility for herds. Biomolecules such as gelatin-binding proteins (GBP) and heparin (HBP) and metabolites participate of several physiological events in the sperm cell until fertilization. Thus, these seminal biomolecules can serves as biomarkers for fertility in several species. Therefore, the objectives of the present study were (1) to identify the GBP and HBP profile in the seminal plasma of farm species and (2) to identify sperm metabolites associated with fertility in Holstein bulls. To achieve the objective of study 1 the seminal plasma of bovine, caprine, ovine, rabbit, equine and swine species were subjected to fast-performance liquid chromatography (FPLC) and mass spectrometry. In addition, bioinformatics tools were used to evaluate the physiological processes which these proteins are involved. The total GBP were in bovine (354), caprine (103), ovine (51), rabbit (146), equine (25) and swine (87) species. Among the most abundant GBP were identified proteins of spermadhesins. The total HBP were in bovine (894), caprine (789), ovine (647), rabbit (600), equine (556) and swine (86) species. The HBP with higher concentrations include bodhesin 2, protein S100, clusterin, PSP-I, PSP-II, among others. In silico analyzes shown that HBP mainly participate in cellular biological processes and have molecular binding function. To achieve the goal of study 2, the sperm metabolites of 10 bulls with high (n = 5) and low (n = 5) fertility were identified through GC-MS technique. In addition, multivariate and univariate statistical analyzes were performed through the MetaboAnalyst 3.0 program to identify metabolites associated with fertility. The results showed that among the 41 different metabolites identified in spermatozoa the levels of four compounds were significantly different and can be used as molecular biomarkers. These metabolites were aminomethane and azelaic acid (higher in spermatozoa of low fertility bulls) and butyric acid and urea (higher in spermatozoa of high fertility bulls). The results of this research are significant because they help to promote basic animal science and the proteins and metabolites identified can be used in reproductive biotechnology to evaluate the semen quality and predict reproductive fertility.

Heparin-binding proteins of seminal plasma in Nellore bulls / Proteínas ligadoras à heparina do plasma seminal em touros Nelore

The aim of this study was to identify heparin-binding proteins (HBPs) in seminal plasma of Nellore (Bos taurus indicus) bulls. Bulls (n=4), 30-36 months old, 500-550kg with satisfactory seminal quality were selected. After the centrifugation, samples of the seminal plasma were pooled and the HBPs were isolated by heparin-affinity chromatography. The recovered HBPs fractions were pooled. One-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDSPAGE) 12.5 percent was performed in vertical minigels. Eight bands with molecular weights ranging from 15 to 63kDa were observed. Two proteins were identified (22 and 25kDa), similar to those previously described in Bos taurus taurus bulls. Other bands identified in this study (39, 53, 58 and 63kDa) have not been previously observed and possibly they are specific to Nellore semen.(AU)

O objetivo deste estudo foi identificar proteínas ligadoras à heparina no plasma seminal de touros Nelore (Bos taurus indicus). Para tanto, foram selecionados quatro touros entre 30 e 36 meses de idade e peso aproximado de 500-550kg. Após centrifugação, amostras do plasma seminal foram misturadas e as proteínas ligadoras à heparina foram isoladas por meio da cromatografia por afinidade. As frações após a eluição foram agrupadas para caracterização das bandas protéicas (SDSPAGE, 12,5 por cento). Foram identificadas oito bandas protéicas variando entre 15 e 63kDa. Duas proteínas com 22 e 25kDa foram similares às descritas em touros Bos taurus taurus. Outras proteínas identificadas com 39, 53, 58 e 63kDa ainda não foram descritas e possivelmente sejam específicas para Bos taurus indicus.(AU)

Estudo comparativo entre heparina sódica e heparina de baixo peso molecular (nadroparina cálcica) em cães (Canis familiaris) submetidos à hemódialise

Durante a realização das sessões de hemodiálise (HD) observam-se alterações relacionadas à coagulação, pelo contato do sangue do paciente com os circuitos extracorpóreos. Essas alterações podem ser decorrentes da ativação dos mecanismos intrínsecos da cascata de coagulação sangüínea, que resultam na formação de trombos. No modelo hemodialítico, utilizam-se substâncias anticoagulantes com a finalidade de prevenir a formação destes trombos. A substância padrão utilizada para anticoagulação em HD é a heparina sódica. As heparina de baixo peso molecular (HBPM) são fragmentos da heparina sódica com muitas vantagens. Exibe uma biodisponibilidade maior, possui menor ligação com proteínas plasmáticas e meia vida superior, resultando desta maneira, menor risco de sangramento. O objetivo principal desta pesquisa foi comparar e avaliar a heparina sódica com HBPM em cães submetidos à HD. Utilizou-se 14 cães que foram divididos em 2 grupos. O primeiro grupo, foi utilizada a heparina sódica e o segundo grupo a HBPM. Para avaliação do sistema hemostático dos animais foram colhidas amostras de sangue durante o período de 3 horas em 4 momentos distintos (M1, M2 e M3) e 24 horas (M4) após o término das sessões de hemodiálise para a realização de provas de coagulação como: tempo de tromboplastina parcial ativada (TTPA), tempo de protombina (TP), tempo de coagulação ativada (TCA), prova Anti-Xa e hemograma completo. Neste estudo a dose padronizada de heparina foi de 100UI/Kg/IV/Bolus com repetição de o da dose 60 e 120 minutos após o inicio, e 125 U anti-Xa/Kg/IV/Bolus com repetição de ? da dose após 90 minutos para HBPM. De acordo com os resultados obtidos nesta pesquisa pode-se concluir que não existiram diferenças estatisticamente significantes quando se utiliza a heparina sódica e HBPM como substâncias anticoagulantes...

Coagulation disturbances, with thrombus formation, are common in hemodialysis due to activation of the intrinsic mechanism of the coagulation cascade. Anticoagulant substances are used for preventing thrombus formation. Heparin is the standard substance used for this purpose. However, heparin has troublesome pharmacokinetics, its clearance is dose dependent, it is highly protein bound and a minimum or threshold level is necessary to achieve an antithrombotic effect. Low molecular weight heparins are depolymerized preparations of heparin with multiple advantages over heparin. They exhibit less binding to cells and proteins and have superior bioavailability, a longer plasma half life and more predictable dose-response characteristics and carry a lower risk of hemorrhage and the immune mediated thrombocytopenia is less common. This research was planned to compare the effect of the low molecular weight heparin with the standard heparin in dogs submitted do hemodialysis. 14 dogs divided in two groups were studied.Group 1 used heparin 50 UI/Kg/IV Bolus with o of the initial dose repeated at 60 and 120 minutes after the beginning of the experiment. Group 2 used Low molecular weight heparin (Nadroparin) 125 U anti aX/kg//IV with a 1/3 of the initial dose repeated 90 minutes after the beginning of the experiment.Blood samples were drawn at 3 hours interval called (M1, M2,M3) and at 24 hours (M4) after ending the hemodialysis session.The coagulation system of the dogs was evaluated by the aPTT, PTT, aCT, aX and hemogram. The patency of the dialytic system was also evaluated. Our results showed no statistically significant differences between the two heparins, and the dose of the low-molecular-weight heparin was standardized for hemodialysis in dogs