RESUMO
Forage technology has been successfully introduced into smallholder cattle systems in Cambodia as an alternative feed source to the traditional rice straw and native pastures, improving animal nutrition and reducing labour requirements of feeding cattle. Previous research has highlighted the positive impacts of forage technology including improved growth rates of cattle and household time savings. However, further research is required to understand the drivers, challenges and opportunities of forage technology for smallholder cattle households in Cambodia to facilitate widespread adoption and identify areas for further improvement. A survey of forage-growing households (n = 40) in July-September 2016 examined forage technology adoption experiences, including reasons for forage establishment, use of inputs and labour requirements of forage plot maintenance and use of forages (feeding, fattening, sale of grass or seedlings and silage). Time savings was reported as the main driver of forage adoption with household members spending approximately 1 h per day maintaining forages and feeding it to cattle. Water availability was reported as the main challenge to this activity. A small number of households also reported lack of labour, lack of fencing, competition from natural grasses, cost of irrigation and lack of experience as challenges to forage growing. Cattle fattening and sale of cut forage grass and seedlings was not found to be a widespread activity by interviewed households, with 25 and 10% of households reporting use of forages for these activities, respectively. Currently, opportunities exist for these households to better utilise forages through expansion of forage plots and cattle activities, although assistance is required to support these households in addressing current constraints, particularly availability of water, if the sustainability of this feed technology for smallholder cattle household is to be established in Cambodia.
Assuntos
Criação de Animais Domésticos/instrumentação , Criação de Animais Domésticos/métodos , Criação de Animais Domésticos/economia , Animais , Camboja , Bovinos , Características da FamíliaRESUMO
Porcine reproductive and respiratory syndrome (PRRS) was first identified in Cambodia in 2010, causing serious problems on affected farms, although the costs of the disease have not been well defined. The household financial impact of a PRRS outbreak in Cambodia was investigated using partial budget analysis, examining the economic benefit of three proposed interventions: (i) quarterly PRRS vaccine use, (ii) biosecurity implementation, and (iii) implementation of vaccination and biosecurity. The analyses were applied to three farm models: (i) a two-sow breeder; (ii) a five-pig fattener; and (iii) a single-sow, three-pig farrow-to-finish/breeder. Data was derived from a knowledge, attitude, and practice survey of 240 smallholder farmers (61 with pigs) from 16 villages across 5 provinces, plus case studies of 12 farmers selected for more detailed financial analysis. The study indicated that financial losses associated with PRRS were severe, with a 25% mean loss to the annual household income of 61 interviewed farmers. Partial budget analysis identified a strongly positive incentive for vaccination and biosecurity to be implemented in combination, with the highest annual net benefit of USD 357.10 realised by the breeder system. However, due to current scarcity of the PRRS vaccine and its high cost to smallholders, biosecurity interventions may be more cost-effective, especially for low PRRS incidence regions. It was concluded that PRRS critically constrains the profitability of smallholder pig farms and that these findings will assist development of village-level livestock disease risk management programmes that encourage adoption of vaccination and biosecurity practices to enhance farmer livelihoods in Cambodia.
Assuntos
Criação de Animais Domésticos/economia , Surtos de Doenças/veterinária , Síndrome Respiratória e Reprodutiva Suína/economia , Vacinação/veterinária , Animais , Camboja , Surtos de Doenças/economia , Surtos de Doenças/prevenção & controle , Fazendeiros , Feminino , Gado , Síndrome Respiratória e Reprodutiva Suína/prevenção & controle , Inquéritos e Questionários , Sus scrofa , Suínos , Vacinação/economiaRESUMO
In Cambodia, the majority of the population is rural and reliant on subsistence agriculture, with cattle raised by smallholder farmers using traditional practices, resulting in low productivity and vulnerability to foot-and-mouth disease (FMD). As FMD causes deleterious impacts on rural livelihoods, known FMD risk factors were reviewed, using knowledge, attitudes and practice (KAP) surveys of smallholders (n = 240) from four regions. The study aimed to understand current biosecurity threats to smallholder livelihoods and investigate the hypothesis that smallholder farmers practising FMD risk management should be associated with higher incomes from cattle. Descriptive data were examined to demonstrate trends in KAP and a multivariable linear regression model developed to identify cattle income predictors. Results showed that baseline mean knowledge scores were low at 28.4% across all regions and basic biosecurity practices, including quarantine of new cattle, isolation of sick cattle and FMD vaccination, were lacking. As farmers purchase and sell cattle from and to various administration levels (including export), there is high risk of FMD transmission into and from smallholder communities. The final multivariable linear regression model identified significant explanatory parameters for annual cattle income, including region, number of calves born, forage plot size (ha), vaccination of cattle and the number of cattle purchased (F pr. < 0.001, R2 = 29.9). Individual biosecurity practices including FMD vaccination were not significant predictors of income. With the current focus of farmers on treatment of FMD with inappropriate antibiotics leading to potential anti-microbial residue issues, yet receptivity to payment for vaccine in most regions, there is an urgent need for a coordinated national biosecurity and FMD management public awareness campaign. Further, to enhance the association between improved cattle health and rural livelihoods, it is recommended that livestock development programmes implement a systems approach to enhance farmer KAP in biosecurity, nutrition, reproduction and marketing of cattle.
Assuntos
Doenças dos Bovinos/prevenção & controle , Controle de Doenças Transmissíveis/métodos , Fazendeiros/psicologia , Febre Aftosa/prevenção & controle , Conhecimentos, Atitudes e Prática em Saúde , Criação de Animais Domésticos/economia , Criação de Animais Domésticos/métodos , Animais , Camboja , Bovinos , Doenças dos Bovinos/virologia , Febre Aftosa/virologiaRESUMO
This study aimed to identify factors associated with cattle reproductive output in rural smallholder farms in Cambodia in order to determine the main causes of reproductive failure and design efficient interventions for improvement. The majority of the nation's beef is produced on smallholder farms where productivity is constrained by poor animal reproductivity reflected in the recent livestock population decline of approximately 13 % from 2009 to 2013. Farmers (n = 240) from 16 villages from five provinces were surveyed in mid-2015 to determine their baseline knowledge, attitude and practices (KAP) associated with cattle reproduction. In addition, 16 case studies from three of these provinces were conducted to provide a more detailed assessment of current cattle reproductive husbandry practices. In order to assess the reproductive impact of previously implemented interventions, an endpoint KAP survey and longitudinal health and husbandry study from three Cambodian provinces conducted between 2008 and 2013 were also analysed. Three multivariable prediction models (two KAP and one longitudinal) identified the following significant factors associated with the reproductive outcomes 'number of calves born' or probability that cows 'gave birth': target feeding (P = 0.074), growing vegetables (P = 0.005), attitudes towards cattle vaccination (P = 0.010), improving bull selection (P = 0.032), local breed use (P = 0.005), number of joining attempts (P < 0.001), discontinuation of animal draught practices (P = 0.003) and retention of breeding animals (P < 0.001). The identification of significant factors and interventions in this study has led to intervention recommendations that can potentially improve reproductive efficiency, combat the declining cattle population and improve smallholder capacity to supply to expanding regional meat demand in South-East Asia and China.
Assuntos
Criação de Animais Domésticos/métodos , Doenças dos Bovinos/epidemiologia , Indústria Alimentícia/métodos , Carne Vermelha , Reprodução , Animais , Cruzamento , Camboja/epidemiologia , Bovinos , Fazendeiros , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Masculino , Análise Multivariada , População Rural , Inquéritos e Questionários , Vacinação/veterináriaRESUMO
A cross-sectional survey of 445 Village Animal Health Workers (VAHWs) from 19 provinces in Cambodia was undertaken. The aim was to establish their levels of training, farm visit frequency, reasons for visits and disease reporting practices, enabling the strengths and weaknesses of the VAHW system in Cambodia to be determined, in providing both a fee-based smallholder livestock clinical service and a government partnership in transboundary animal disease (TAD) surveillance and control. The study used 'guided group interviews' and identified that VAHWs had good contact with farmers with 61.5% making more than one farm visit daily. However, incomes from services remained low, with 45% VAHWs obtaining between 20 and 40% of their household income from VAHW activities. VAHWs recorded relatively high rates of disease reporting, with 72% claiming they report diseases immediately and 74% undertaking monthly reporting to veterinary authorities. Logistic regression analysis revealed VAHW contact frequency with district and/or provincial officers was associated with more VAHW farm visits, and frequency of VAHW visits to smallholder farms was positively associated with average monthly expenditure on animal medication and equipment. This suggests that increased veterinary extension to VAHWs and access to veterinary equipment, vaccines and drugs may further increase VAHW-farmer engagement. VAHWs provide an accessible, market-based, animal health 'treatment and reporting' service linked to livestock smallholders across Cambodia. However, for improved TAD prevention and more efficient control of outbreaks, research that assesses provision of an animal health 'preventive-based' business model is urgently needed to reduce both the costs to farmers and the risks to the economy due to foot-and-mouth disease and other TADs in Cambodia.
Assuntos
Doenças dos Bovinos/prevenção & controle , Surtos de Doenças/prevenção & controle , Fazendeiros , Pessoal de Saúde , Criação de Animais Domésticos , Animais , Camboja , Bovinos , Doenças dos Bovinos/transmissão , Estudos Transversais , Feminino , Humanos , MasculinoRESUMO
Foot and mouth disease (FMD) is endemic in Cambodia and throughout the Greater Mekong Subregion and causes significant losses to rural smallholders owning the majority of the national large ruminant population. However, due to underreporting, paucity of knowledge of FMD impacts, limited veterinary capacity and deficits of data available for analysis, the quantifiable benefits of a national FMD control programme are unknown. To address this deficit, existing literature and research data from the 'Best practice health and husbandry of cattle, Cambodia' project conducted between 2007 and 2012, were used to develop a three-phase analysis framework to: assess the impacts of the recent widespread FMD epizootic in Cambodia in 2010, conduct a value chain analysis of the large ruminant market and estimate the costs and benefits for a national large ruminant biannual FMD vaccination programme. A trader survey conducted in 2010-2011 provided cattle and buffalo value chain information and was matched to village herd structure data to calculate a total large ruminant farm-gate value of USD 1.271 billion in 2010. Monte Carlo simulation modelling that implemented a 5-year biannual vaccination programme at a cost of USD 6.3 an animal per year identified a benefit-cost ratio of 1.40 (95% CI 0.96-2.20) when accounting for recent prices of cattle and buffalo in Cambodia and based on an expected annual incidence of 0.2 (assuming one major epizootic in the 5-year vaccination programme). Given that the majority of the large ruminants are owned by rural smallholders, and mostly the poor are involved in agricultural employment, the successful implementation of an FMD control programme in Cambodia would be expected to avoid estimated losses of USD 135 million; equivalent to 10.6% of the 2010 farm-gate value and contributing to important reductions in rural poverty and food insecurity.
Assuntos
Febre Aftosa/prevenção & controle , Vacinação/economia , Vacinas Virais , Animais , Búfalos , Camboja , Bovinos , Doenças dos Bovinos/economia , Doenças dos Bovinos/prevenção & controle , Análise Custo-Benefício , Febre Aftosa/economia , Método de Monte CarloRESUMO
Haemorrhagic septicaemia (HS) is an acute fatal infectious disease of mainly cattle and buffalo and outbreaks occur commonly in Cambodia. Disease outbreak reports were examined to select five villages from three provinces for a retrospective investigation of HS epidemiology and socioeconomic impact on smallholders, with an aim of identifying potential benefits from improving disease prevention through biosecurity and vaccination. The Village Animal Health Worker (VAHW) or Chief in each village and 66 affected smallholders were surveyed. At the village level, 24% of all households were affected with an estimated mean village herd morbidity of 10.1% and mortality of 28.8%. Affected farmers reported HS disease morbidity and mortality at 42.7% and 63.6% respectively. Buffalo had a higher morbidity (OR = 2.3; P = 0.003) and mortality (OR = 6.9; P < 0.001) compared with cattle, and unvaccinated large ruminants a higher morbidity (OR = 2.9; P = 0.001). The financial impact varied depending on whether the animal survived, provision of treatment, draught replacement and lost secondary income. The mean cost per affected household was USD 952.50 based on ownership of five large ruminants. The impact per affected animal was USD 375.00, reducing the pre-disease value by 66.1%. A partial budget revealed an overwhelming incentive for farmers to practice biannual vaccination, with a net benefit of USD 951.58 per household based on an annual disease incidence rate of 1. Sensitivity analysis showed that a net benefit of USD 32.42 remained based on an outbreak every 20 years. This study indicates HS can cause a catastrophic financial shock to smallholders and remains a critical constraint to improving large ruminant productivity and profitability. Addressing HS disease control requires a focus on improving smallholder farmer knowledge of biosecurity and vaccination and should be priority to stakeholders interested in addressing regional food insecurity and poverty reduction.
Assuntos
Criação de Animais Domésticos , Doenças dos Bovinos/epidemiologia , Surtos de Doenças/veterinária , Fazendeiros , Septicemia Hemorrágica/veterinária , Animais , Búfalos , Camboja/epidemiologia , Bovinos , Doenças dos Bovinos/economia , Doenças dos Bovinos/prevenção & controle , Demografia , Surtos de Doenças/economia , Feminino , Septicemia Hemorrágica/economia , Septicemia Hemorrágica/epidemiologia , Septicemia Hemorrágica/prevenção & controle , Humanos , Masculino , Estudos Retrospectivos , Ruminantes , Inquéritos e Questionários , Vacinação/veterináriaRESUMO
Conservationists are increasingly engaging with the concept of human well-being to improve the design and evaluation of their interventions. Since the convening of the influential Sarkozy Commission in 2009, development researchers have been refining conceptualizations and frameworks to understand and measure human well-being and are starting to converge on a common understanding of how best to do this. In conservation, the term human well-being is in widespread use, but there is a need for guidance on operationalizing it to measure the impacts of conservation interventions on people. We present a framework for understanding human well-being, which could be particularly useful in conservation. The framework includes 3 conditions; meeting needs, pursuing goals, and experiencing a satisfactory quality of life. We outline some of the complexities involved in evaluating the well-being effects of conservation interventions, with the understanding that well-being varies between people and over time and with the priorities of the evaluator. Key challenges for research into the well-being impacts of conservation interventions include the need to build up a collection of case studies so as to draw out generalizable lessons; harness the potential of modern technology to support well-being research; and contextualize evaluations of conservation impacts on well-being spatially and temporally within the wider landscape of social change. Pathways through the smog of confusion around the term well-being exist, and existing frameworks such as the Well-being in Developing Countries approach can help conservationists negotiate the challenges of operationalizing the concept. Conservationists have the opportunity to benefit from the recent flurry of research in the development field so as to carry out more nuanced and locally relevant evaluations of the effects of their interventions on human well-being.
Assuntos
Conservação dos Recursos Naturais , Países em Desenvolvimento , Qualidade de Vida , HumanosRESUMO
To better understand how smallholder farmers whom own the majority of Cambodian cattle can contribute to efforts to address food security needs in the Mekong region, a five-year research project investigating methods to improve cattle health and husbandry practices was conducted. Cattle production in Cambodia is constrained by transboundary animal diseases (TADs) including foot-and-mouth disease (FMD) and haemorrhagic septicaemia (HS) plus poor nutrition, reproduction and marketing knowledge. The project worked in six villages in Kandal, Takeo and Kampong Cham province during 2007-12. Farmers from three 'high intervention' (HI) villages incrementally received a participatory extension programme that included FMD and HS vaccination, forage development and husbandry training. Evaluation of project impacts on livelihoods was facilitated by comparison with three 'low intervention' (LI) villages where farmers received vaccinations only. Results of knowledge, attitude and practice (KAP) and socio-economic surveys conducted in 2012 of 120 participating farmers identified that farmer knowledge in the HI project sites exceeded LI sites on the topics of biosecurity, internal parasites, nutrition and reproduction. HI farmers adopted biosecurity practices including a willingness to vaccinate for FMD and HS at their own cost, separate sick from healthy cattle, grow and feed forages and displayed awareness of the benefits of building fattening pens. HI farmers that grew forages observed time savings exceeding two hours per day each for men, women and children, enabling expansion of farm enterprises, secondary employment and children's schooling. Logistic regression analysis revealed that farmers in the HI group significantly increased annual household income (P < 0.001), with 53% reporting an increase of 100% or more. We conclude that improving smallholder KAP of cattle health and production can lead to improved livelihoods. This strategy should be of interest to policymakers, donors, researchers and extension workers interested in addressing TAD control, food insecurity and rural poverty in Southeast Asia.
Assuntos
Criação de Animais Domésticos/economia , Criação de Animais Domésticos/métodos , Fenômenos Fisiológicos da Nutrição Animal/fisiologia , Doenças dos Bovinos/prevenção & controle , Febre Aftosa/prevenção & controle , Conhecimentos, Atitudes e Prática em Saúde , Septicemia Hemorrágica/veterinária , Agricultura , Criação de Animais Domésticos/educação , Animais , Camboja , Bovinos , Feminino , Septicemia Hemorrágica/prevenção & controle , Modelos Logísticos , Masculino , Inquéritos e Questionários , Vacinação/veterináriaRESUMO
The financial impact of an outbreak of FMD in 2010 on 62 smallholder cattle farmers in four villages in southern Cambodia was investigated by a financial impact survey questionnaire. Financial losses associated with FMD infection were severe with variation depending on whether the animal survived or died or was used for draft. The average post-FMD loss varied from USD 216.32, a 54% reduction from the pre-FMD value because of weight loss and treatment costs, to USD 370.54, a 92% reduction from pre-FMD values if the animal was treated, died and a rental draft replacement was required. Partial budget analysis identified a strongly positive incentive for cattle to be vaccinated biannually for FMD, providing USD 31.48 per animal for each animal owned. However low vaccination rates suggest that farmers are mostly unaware of the need or averse to the practice of vaccinating their cattle for FMD. This may be due to poor understanding of preventative disease strategies such as vaccination, unavailable disposable income for purchase of vaccines, and failure to recognize the full costs that are incurred when the disease occurs. Enhancing smallholder cattle productivity through the introduction of forage growing systems has been suggested as a pathway for alleviating rural poverty in the Mekong region. As our financial analysis identified a net benefit of vaccination for smallholder farmer enterprises in an endemic FMD area in Cambodia, it is considered important that farmer education strategies aimed at improving cattle productivity, also include both access to vaccine and training in preventative disease risk management and biosecurity practices in Cambodia.
Assuntos
Criação de Animais Domésticos/economia , Doenças dos Bovinos/economia , Surtos de Doenças/veterinária , Febre Aftosa/economia , Vacinação/veterinária , Vacinas Virais/economia , Adulto , Agricultura , Animais , Camboja/epidemiologia , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/prevenção & controle , Surtos de Doenças/economia , Surtos de Doenças/prevenção & controle , Feminino , Febre Aftosa/epidemiologia , Febre Aftosa/prevenção & controle , Humanos , Masculino , Pessoa de Meia-Idade , Inquéritos e Questionários , Vacinas Virais/uso terapêuticoRESUMO
Farmer knowledge surveys were conducted in 2008 and 2010 in Cambodia to evaluate the impact of a research project studying interventions that can improve cattle production and health, including biosecurity and practices relating to risks of transmission of transboundary diseases. The project hypothesis is that by increasing the value of smallholder-owned large ruminants through nutritional interventions and improved marketing, knowledge-based interventions including risk management for infectious diseases such as foot-and-mouth disease (FMD) can be implemented into a more sustainable pathway for rural development. Between 2008 and 2010, significant improvements in farmer knowledge and attitudes were recorded in three villages in three provinces of southern Cambodia. This was achieved through participatory 'applied field research', 'on the job' training plus 'formal' training programmes. No cases of FMD were recorded during the study period in the 'high-intervention' (HI) villages despite the common occurrence of the disease in a nearby 'low-intervention' and many other villages in the three provinces. Whilst it is likely that protection of these villages from FMD infection was from increasing the herd immunity by vaccination, it could also have been partly because of a decrease in risk behaviours by farmers as a result of their increasing knowledge of biosecurity. The research indicates that smallholder farmers are motivated by nutritional interventions that improve the value of their cattle 'bank' and offer better marketing opportunities. This provides a more receptive environment for introduction of disease risk management for infectious and other production limiting diseases, best implemented for smallholder farmers in Cambodia by intensive training programmes. In lieu of a widespread public awareness programme to deliver mass education of smallholder farmers in disease prevention and biosecurity, livestock development projects in South-East Asia should be encouraged to include training in disease risk management as an important intervention if the current momentum for trade in large ruminant livestock and large ruminant meat is to continue to progress and contribute to addressing global food security concerns.
Assuntos
Criação de Animais Domésticos/métodos , Doenças dos Bovinos/prevenção & controle , Adulto , Criação de Animais Domésticos/educação , Animais , Camboja/epidemiologia , Bovinos , Doenças dos Bovinos/epidemiologia , Controle de Doenças Transmissíveis , Doenças Transmissíveis/transmissão , Doenças Transmissíveis/veterinária , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Entrevistas como Assunto , Masculino , Pessoa de Meia-Idade , Fatores SocioeconômicosRESUMO
Farmer's cattle were treated with triclabendazole and used as tracer animals to detect new infections with Fasciola gigantica in three villages located on the bank of the Bassac River (a major tributary of the Mekong River) and in a fourth village located on farmland away from the river, from April 1999 until January 2001. The month of infection was estimated by subtracting 4 months from the date when eggs of F. gigantica were detected in faeces. Farmers were interviewed each month to record the nature of the agricultural and animal husbandry activities that occurred during the previous month, especially events that might have exposed cattle to infection with F. gigantica. Results support the conclusions that infection of cattle in riverbank villages acquired from about August or September until November originated from herbage and water in irrigation canals and dams on the riverbank, and that the progressively increasing monthly incidence from December until April (up to 87% per month in April 2000) was derived from herbage and water in recently harvested rice fields and lakes adjacent to the riverbank. The abrupt cessation of new infection in riverbank villages in May coincided with flooding of low-lying land, the movement of cattle to land above flood height on the riverbank, and a change of diet to dry-land crop residues, stored dry rice stalks, and herbage and water that were unlikely to contain metacercariae. It was concluded that snails in dams and canals on the riverbank became infected with E gigantica after cattle were moved to the riverbank in May, and cercariae shed from these snails provided the new infections that occurred in cattle in August and September. In the village located away from the river, infection of cattle between September and March coincided with the rice harvest, supporting the conclusion that feeding of fresh rice stalks and stubble after the rice was harvested was the main source of infection. The low monthly incidence observed (up to 6.4% per month) was consistent with the hypothesis that snails did not survive in the dry rice fields between crops and that few snails would have been available from the small number of aquatic refuges that persisted through the dry season to recolonize rice fields during the wet season. Between April and August there was no opportunity for new infection because cattle were fed forage from around houses and headlands, and on dry-land crop residues and stored dry rice stalks. Control of fasciolosis was proposed using a single treatment of cattle with triclabendazole in riverbank villages in May when cattle were moved to the riverbank, and after harvest of the last rice field in villages located away from the river.
Assuntos
Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/parasitologia , Fasciola/crescimento & desenvolvimento , Fasciolíase/veterinária , Hepatopatias/veterinária , Animais , Camboja/epidemiologia , Bovinos , Fasciolíase/epidemiologia , Fasciolíase/parasitologia , Fezes/parasitologia , Feminino , Incidência , Hepatopatias/epidemiologia , Hepatopatias/parasitologia , Masculino , Contagem de Ovos de Parasitas/veterinária , População Rural , Estações do AnoRESUMO
Cell replacement therapy in Parkinson's disease depends on a reliable source of purified dopamine (DA) neurons (PDN) and the identification of factors relevant to their survival. Our goal was to genetically tag and purify by flow cytometry embryonic midbrain DA neurons from a transgenic mouse line carrying 11 kb of human tyrosine hydroxylase promoter driving expression of the enhanced green fluorescent protein (GFP) for studies in vivo and in vitro. A 99% purification of GFP(+) cells was achieved. When transplanted into 6-hydroxydopamine-treated rat striatum, PDN survived, became well-integrated and produced recovery from amphetamine-induced motor behaviors. However, when grown in culture, PDN died within days of plating. No known growth factors prevented PDN death as did incubation with novel factors in glia/glial-conditioned media. We conclude that GFP-tagged DA neurons can be purified to homogeneity and can survive and function when grown with glial factors in vitro or after transplantation in vivo.
Assuntos
Transplante de Tecido Encefálico , Transplante de Tecido Fetal , Neuroglia/fisiologia , Neurônios/citologia , Neurônios/transplante , Doença de Parkinson/terapia , Animais , Técnicas de Cultura de Células/métodos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Meios de Cultivo Condicionados/farmacologia , Dopamina/fisiologia , Citometria de Fluxo , Sobrevivência de Enxerto , Proteínas de Fluorescência Verde/genética , Substâncias de Crescimento/fisiologia , Camundongos , Camundongos Transgênicos , Neuroglia/citologia , Neurônios/fisiologia , Ratos , Ratos Endogâmicos F344RESUMO
Cell replacement therapy in Parkinson's disease depends on a reliable source of purified dopamine (DA) neurons (PDN) and the identification of factors relevant to their survival. Our goal was to genetically tag and purify by flow cytometry embryonic midbrain DA neurons from a transgenic mouse line carrying 11 kb of human tyrosine hydroxylase promoter driving expression of the enhanced green fluorescent protein(GFP) for studies in vivo and in vitro. A 99% purification of GFP+ cells was achieved. When transplanted into 6-hydroxydopamine-treated rat striatum, PDN survived, became well-integrated and produced recovery from amphetamine-induced motor behaviors. However, when grown in culture, PDN died within days of plating. No known growth factors prevented PDN death as did incubation with novel factors in glia/glial-conditioned media. We conclude that GFP-tagged DA neurons can be purified to homogeneity and can survive and function when grown with glial factors in vitro or after transplantation in vivo.