The proliferation and differentiation of primary pig preadipocytes is suppressed when cultures are incubated at 37°Celsius compared to euthermic conditions in pigs

Abstract

Given similarities in metabolic parameters and cardiovascular physiology, the pig is well positioned as a biomedical model for metabolic disease and obesity in humans. Better understanding molecular mechanisms governing porcine adipocyte hyperplasia may provide insight into the regulation of adipose tissue development that is useful both when considering the pig as a commodity and when extrapolating porcine data to human disease. Primary cultures of pig stromal-vascular cells have served as a useful tool for investigating factors that regulate preadipocyte proliferation and differentiation. However, such cultures have generally been maintained at 37°C in vitro despite euthermia being 39°C in pigs. To address potential concerns about the physiological relevance of culturing primary pig preadipocytes under what would be hypothermic conditions in vivo, the objective of this study was to investigate the effect of culture temperature on the proliferation and differentiation of pig preadipocytes in primary culture. Culturing primary preadipocytes at 37 rather than 39°C decreases their proliferation rates based upon cleavage of the tetrazolium salt, MTT (P < 0.001), reduction of resazurin (P < 0.001), and daily cell counts (P < 0.001). Likewise, culturing primary porcine preadipocytes at 37°C suppressed their adipogenic potential based upon monitoring adipogenesis morphologically, biochemically, and via the expression of mRNA encoding adipogenic marker genes. Collectively, these data indicate the proliferation and differentiation of primary pig preadipocytes is suppressed when cultures are incubated at 37°C compared to normal body temperature of pigs. This may confound investigation of factors that impact adipocyte hyperplasia in the pig.

Keywords:

• adipocyte
• adipogenesis
• biomedical
• hyperplasia
• preadipocyte
• primary culture
• proliferation
• swine
• temperature

Abbreviations:

• CA3, carbonic anhydrase III
• C/EBPα, CCAAT/enhancer-binding protein α
• C/EBPβ, CCAAT/enhancer-binding protein β
• COUP-TF1, chicken ovalbumin protein transcription factor 1
• COUP-TF2, chicken ovalbumin protein transcription factor 2
• DGAT2, diacylglycerol O-acyltransferase 2
• ECM, extracellular matrix
• FMO1, flavin containing monooxygenase 1
• GPDH, glycerol-3-phosphate dehydrogenase
• ITIH3, inter-α (globulin) inhibitor H3
• MTT, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide
• OROSM, Oil Red O-stained material
• PFKFB1, 6-phosphofructo-2-kinase/fructose-2, 6-biphosphatase 1
• PPARγ, peroxisome proliferator-activated receptor gamma
• PTFβ, pleiotrophic factor β
• RIN, RNA Integrity Number
• RT-PCR, real-time polymerase chain reaction
• SAL1, salivary lipocalin
• S-V cells, stromal-vascular cells
• TN-X, tenascin-X
• TNFα, tumor necrosis factor α

Disclosure of Potential Conflicts of Interest

No potential conflicts of interest were disclosed.