The authors acknowledge funding sources responsible for this work: 5K12HD055929 (HHR), 5R01NS080180-02 (DDF).

NOTE: All animal procedures in this protocol are conducted with the approval of University of Florida Institutional Animal Care and Use Committee (IACUC) and are in compliance with the &#39;Guide for the Care and Use of Laboratory Animals&#39;.
1. Basic Experimental Set up Before Intermittent Hypoxia Administration
<ol>
	<li>Expose pups12 to the different gas mixes using a whole-body mouse plethysmograph chambers in much the same manner as adult rodents for other experimental purp...

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The authors have nothing to disclose.

This work reports the development of a protocol to expose neonatal rodents to AIH. The parameters described here effectively alter in situ neural stem cell biology, which is observable over several rounds of cell passage. Specifically, AIH increases the number of non-adherent neurospheres, the expansion of cells within each neurosphere (refected by sphere diameter), the expansion of adherent NPC populations, and the presence of neuroblasts in both non-adherent and adherent populations. It should be emph...

The goal of this method is to reproducibly and effectively deliver intermittent bouts of systemic lowered ambient oxygen to neonatal rodents. The rationale for using intermittent hypoxia (IH) to manipulate stem cell biology originates from in vitro cell culture experiments in which O2 content of the growth media is altered. Specifically, when compared to &#8220;standard&#8221; conditions of 20% O2, extended culture of stem/progenitor cell populations cells in 3% O2 results in increased proliferation, decreased apoptosis and increased neuronal yield1,2.
This group has significant experience with the administration of systemic IH, and has conducted extensive studies on the role of IH in respiratory plasticity3-7. This work, and the recent finding that chronic IH increased neurogenesis in the rodent CNS8-10, forms the basis for the exploration of acute in vivo hypoxia as a preconditioning stimulus (i.e., prior to tissue harvest) on the subsequent culture of neural stem/progenitor cells (NPCs)11. Remarkably, when mouse pups were exposed to a brief (&#60;1 hr) period of acute intermittent hypoxia (AIH), cells that were harvested from the subventricular zone (SVZ) had significantly increased capacity for expansion as neurospheres or adherent monolayer cells. The AIH protocol was also associated with increased expression of a &#8220;neuronal fate&#8221; transcription factor (Pax6).
Accordingly, in vivo AIH protocols may provide a means to &#8220;prime&#8221; NPCs prior to culture. For example, applications for this approach could include expanding cell populations prior to transplantation into the injured central nervous system, or simply increasing the neuronal differentiation of cultured cells prior to in vitro experiments. Further, because this is a systemic delivery, any organ, tissue or cell is a candidate for similar study. Therefore, the protocol as written is potentially applicable to a wide range of studies on intermittent oxygen manipulation in small mammals.
There are certain advantages to this approach. In other published work, neonates were treated as a litter with the dam in hypobaric chambers, which allows for chronic dosing, less handling prior to treatment, and maintained maternal contact during treatment9. The current approach bypasses repeated treatments to a breeding female, or the use of a different dam for each experiment. This protocol also allows study of precise litter-matched and age-matched neonates. Representative data demonstrate another key strength of this protocol, namely the rapidity with which AIH, as delivered, elicits a powerful and consistent biological response in neural stem cell biology. This establishes a precedent for this protocol to elicit tissue- and cellular-level biological changes that alter cell biology.
This report will outline the detailed procedures used for exposing rodent pups to AIH as well as the population analysis of SVZ cells grown as neurospheres.

<table border="0" cellpadding="0" cellspacing="0" width="768">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Name of Material/ Equipment</td>
			<td style="width:147px;">Company</td>
			<td style="width:136px;">Catalog Number</td>
			<td style="width:243px;">Comments/Description</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Mouse plethysmography chambers</td>
			<td style="width:147px;">Buxco</td>
			<td style="width:136px;">PLY4211</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Flow meter&#160;</td>
			<td style="width:147px;">Porter</td>
			<td style="width:136px;">F150</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Bias flow unit</td>
			<td style="width:147px;">AFPS</td>
			<td style="width:136px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Baseline Gas Mix</td>
			<td style="width:147px;">Airgas</td>
			<td style="width:136px;">AIZ300</td>
			<td>Compressed Air</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Hypoxic Gas Mix</td>
			<td style="width:147px;">Airgas</td>
			<td style="width:136px;">X03NI72C2000189</td>
			<td>10% Oxygen, balance nitrogen</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Oxygen Meter</td>
			<td style="width:147px;">Teledyne</td>
			<td style="width:136px;">AX-300</td>
			<td></td>
		</tr>
	</tbody>
</table>

delivery of in vivo acute intermittent hypoxia in neonatal rodents to prime subventricular zone-derived neural progenitor cell cultures

Extended culture of neural stem/progenitor cells facilitates in vitro analyses to understand their biology while enabling expansion of cell populations to adequate numbers prior to transplantation. Identifying approaches to refine this process, to augment the production of all CNS cell types (i.e., neurons), and to possibly contribute to therapeutic cell therapy protocols is a high research priority. This report describes an easily applied in vivo &#8220;pre-conditioning&#8221; stimulus which can be delivered to awake, non-anesthetized animals. Thus, it is a non-invasive and non-stressful procedure. Specifically described are the procedures for exposing mouse or rat pups (aged postnatal day 1-8) to a brief (40-80 min) period of intermittent hypoxia (AIH). The procedures included in this video protocol include calibration of the whole-body plethysmography chamber in which pups are placed during AIH and the technical details of AIH exposure. The efficacy of this approach to elicit tissue-level changes in the awake animal is demonstrated through the enhancement of subsequent in vitro expansion and neuronal differentiation in cells harvested from the subventricular zone (SVZ). These results support the notion that tissue level changes across multiple systems could be observed following AIH, and support the continued optimization and establishment of AIH as a priming or conditioning modality for therapeutic cell populations.

The initial experiments, based on historical data, were conducted using 1 min cycle lengths. Based on the subsequent calibrations performed in Step 2 above, it was determined that the O2 level in the chamber was 13% at 1 min post-hypoxia flushing and, that it took a similar time to return to the 21% baseline. However, a 2 min&#160;cycle was sufficient to both achieve 10% oxygen and a return to 21% during the &#8220;baseline&#8221; cycle. Subsequently, 2 min cycle lengths have been used. The protocol duration c...

Watch this Scientific Journal Video about Delivery of In Vivo Acute Intermittent Hypoxia in Neonatal Rodents to Prime Subventricular Zone-derived Neural Progenitor Cell Cultures at JoVE.com

Delivery of In Vivo Acute Intermittent Hypoxia in Neonatal Rodents to Prime Subventricular Zone-derived Neural Progenitor Cell Cultures

This article describes the methodology for administering short periods of intermittent hypoxia to postnatal day 1-8 mouse or rat pups. This approach effectively elicits a robust tissue level &#8220;priming effect&#8221; on cultured neural progenitor cells that are harvested within 30 min of hypoxia exposure.

Delivery of In Vivo Acute Intermittent Hypoxia in Neonatal Rodents to Prime Subventricular Zone-derived Neural Progenitor Cell Cultures

Extended culture of neural stem/progenitor cells facilitates in vitro analyses to understand their biology while enabling expansion of cell populations to ...

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Developmental Biology

7.2K visualizações.  University of Florida.  Este artigo descreve a metodologia para a administração de curtos períodos de hipóxia intermitente para pós-natal 1-8 dia ratinho ou um rato filhotes. Esta abordagem suscita efectivamente um nível do tecido robusto "efeito priming" sobre as células progenitoras neurais em cultura que são colhidas no prazo de 30 min de exposição hipóxia. 