Culture Conditions that Support Expansion and Chondrogenesis of Middle-Aged Rat Mesenchymal Stem Cells

Abstract

Objective Rats are an early preclinical model for cartilage tissue engineering, and a practical species for investigating the effects of aging. However, rats may be a poor aging model for mesenchymal stem cells (MSCs) based on laboratory reports of a severe decline in chondrogenesis beyond young adulthood. Such testing has not been conducted with MSCs seeded in a scaffold, which can improve the propensity of MSCs to undergo chondrogenesis. Therefore, the objective of this study was to evaluate chondrogenesis of middle-aged rat MSCs encapsulated in agarose. Design MSCs from 14- to 15-month-old rats were expanded, seeded into agarose, and cultured in chondrogenic medium with or without 5% serum for 15 days. Samples were evaluated for cell viability and cartilaginous extracellular matrix (ECM) accumulation. Experiments were repeated using MSCs from 6-week-old rats. Results During expansion, middle-aged rat MSCs demonstrated a diminishing proliferation rate that was improved ~2-fold in part by transient exposure to chondrogenic medium. In agarose culture in defined medium, middle-aged rat MSCs accumulated ECM to a much greater extent than negative controls. Serum supplementation improved cell survival ~2-fold, and increased ECM accumulation ~3-fold. Histological analysis indicated that defined medium supported chondrogenesis in a subset of cells, while serum-supplementation increased the frequency of chondrogenic cells. In contrast, young rat MSCs experienced robust chondrogenesis in defined medium that was not improved with serum-supplementation. Conclusions These data demonstrate a previously-unreported propensity of middle-aged rat MSCs to undergo chondrogenesis, and the potential of serum to enhance chondrogenesis of aging MSCs.

Polyethylene glycol precipitation is an efficient method to obtain extracellular vesicle-depleted fetal bovine serum

“…It seemed the initial 96-hour EVdFBS exposure affected chondrogenic differentiation ability of hADSCs. Indeed, it was reported that serum-supplementation could increase the frequency of chondrogenic cells and ECM accumulation to enhance chondrogenesis of aging MSCs [ 36 ]. Therefore, using serum-free culture media for MSCs culture and EVs enrichment might cause cells to go into adaptation and survival mode, and change the cargo of their EVs and therapeutic property, making further research inaccurate [ 37 , 38 ].…”

Sexual Dimorphism in Relation to Structural Changes in Renal Cortex in Different Age Groups: Possible Role of Endogenous SCs

“…Additionally, in case of tissue injury that occurs usually with aging, expansion of progenitor population can occur resulting in an increase in the number [48] . Recently, it was proved that young rat MSCs experienced robust tissue genesis [49] . It was confirmed that reduced regenerative capacity of aged stem cells hampers organ regeneration, but not migration due to injury [50] .…”

Gene expression profiling of progenitor cells isolated from rat rotator cuff musculotendinous junction

“…We used the term progenitors for the cultured cells, but they are more of a heterogeneous population of cells. To establish the 'progenitor cell nature' of the cultures, they were established following methodologies previously described for progenitor cell culture and expansion from equine, bovine and mouse tissue sources [14,15]. Finally, the cell populations in rat rotator cuff can be different from human rotator cuff especially given the fact that humans don't use the upper extremity for ambulatory weight bearing in addition to the inherent biological differences.…”