Unternehmen in der sozial-ökologischen Transformation

Einführung in das Schwerpunktthem

Transformative Potenziale von Unternehmen, die nicht wachsen wollen

Sozial-ökologischer Wandel erfordert eine radikale Veränderung unserer Märkte durch nachhaltige Angebote. Die Annahme, dass hierfür die guten Unternehmen bloß wachsen müssten, greift aber zu kurz. Postwachstumsunternehmen verändern Märkte und Wirtschaftsweisen auch, wenn sie selbst nicht wachsen wollen

Unternehmen als Mitgestalter sozial-ökologischer Transformation: Thesen des Instituts für ökologische Wirtschaftsforschung (IÖW)

Sozial-ökologischer Wandel braucht auch unternehmerisches Handeln. Herkömmliche Konzepte nachhaltiger Unternehmensführung greifen hier jedoch zu kurz. Es ist höchste Zeit, eine Diskussion über transformatives Unternehmenshandeln zu führen

Unternehmen in der sozial-ökologischen Transformation

Einführung in das Schwerpunktthem

Organotypic brain slice cultures of adult transgenic P301S mice--a model for tauopathy studies.

BACKGROUND: Organotypic brain slice cultures represent an excellent compromise between single cell cultures and complete animal studies, in this way replacing and reducing the number of animal experiments. Organotypic brain slices are widely applied to model neuronal development and regeneration as well as neuronal pathology concerning stroke, epilepsy and Alzheimer's disease (AD). AD is characterized by two protein alterations, namely tau hyperphosphorylation and excessive amyloid β deposition, both causing microglia and astrocyte activation. Deposits of hyperphosphorylated tau, called neurofibrillary tangles (NFTs), surrounded by activated glia are modeled in transgenic mice, e.g. the tauopathy model P301S. METHODOLOGY/PRINCIPAL FINDINGS: In this study we explore the benefits and limitations of organotypic brain slice cultures made of mature adult transgenic mice as a potential model system for the multifactorial phenotype of AD. First, neonatal (P1) and adult organotypic brain slice cultures from 7- to 10-month-old transgenic P301S mice have been compared with regard to vitality, which was monitored with the lactate dehydrogenase (LDH)- and the MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays over 15 days. Neonatal slices displayed a constant high vitality level, while the vitality of adult slice cultures decreased significantly upon cultivation. Various preparation and cultivation conditions were tested to augment the vitality of adult slices and improvements were achieved with a reduced slice thickness, a mild hypothermic cultivation temperature and a cultivation CO(2) concentration of 5%. Furthermore, we present a substantial immunohistochemical characterization analyzing the morphology of neurons, astrocytes and microglia in comparison to neonatal tissue. CONCLUSION/SIGNIFICANCE: Until now only adolescent animals with a maximum age of two months have been used to prepare organotypic brain slices. The current study provides evidence that adult organotypic brain slice cultures from 7- to 10-month-old mice independently of the transgenic modification undergo slow programmed cell death, caused by a dysfunction of the neuronal repair systems

Quantification of the LDH release over a period of 15 days under various preparation and cultivation conditions for adult organotypic brain slice cultures^*.

*<p>Values are given as percentage of the released total LDH ± standard deviation. n = 11–12 (NHS: normal horse serum; SPP: survival promoting peptide; BHT: butylated hydroxytoluene; AsODN: antisense oligodesoxynucleotides).</p

TUNEL staining combined with immunohistochemical labeling of astrocytes in adult organotypic brain slices.

<p>Apoptotic cell nuclei (green), astrocytes (red) and cell nuclei (blue) were visualized by TUNEL staining, anti-GFAP and Hoechst, respectively, in the somatosensory cortex (layer VI) of directly fixed (30 µm) and sub-sectioned (30 µm) cultivated brain slices of adult P301S mice (wt/tg mixed). A–C: directly fixed tissue; D–F: tissue treated with staurosporine and fixed on 1^st DIV; G–I: tissue fixed on 1^st DIV; J–L: tissue fixed on 15^th DIV. A, D, G, J: TUNEL; B, E, H, K: GFAP; C, F, I, L: merged images of TUNEL, GFAP and Hoechst. Scale bar 20 µm.</p

Quantification of the metabolism rate (MTT assay) over a period of 15 days under various preparation and cultivation conditions for adult organotypic brain slice cultures^*.

*<p>Values are given as absorbance (562 nm–690 nm) per slice volume [AU/µm³] ± standard deviation. n = 7–8 (NHS: normal horse serum; SPP: survival promoting peptide; BHT: butylated hydroxytoluene; AsODN: antisense oligodesoxynucleotides).</p

Immunohistochemical labeling of astrocytes (GFAP/S100B) in adult organotypic brain slices.

<p>GFAP (red), S100B (green) and cell nuclei (Hoechst, blue) in the somatosensory cortex (layer VI) of cultivated brain slices (200 µm) of adult wild type P301S mice. A–C: tissue fixed on 1^st DIV; D–F: tissue fixed on 7^th DIV; A, D: GFAP; B, E: S100B; C, F: merged images of GFAP, S100B and Hoechst. Scale bar 20 µm.</p

Metabolism rate and cellular necrosis in neonatal and adult organotypic brain slice cultures.

<p>A and C: Reliability of MTT and LDH assays shown by a concentration dependent Triton X-100 induced cell death in adult organotypic brain slice cultures. B and D: Cellular metabolism rate (B) and cellular necrosis (D) in neonatal and adult organotypic brain slice cultures. n = 12 (MTT assay), n = 9 (LDH assay), ***p<0.001, **p<0.01.</p