Effect of limited nutrition on in situ intervertebral disc cells under simulated-physiological loading.
METHODS
Whole ovine caudal intervertebral discs (IVD) were cultured in sufficient and limited nutrition under simulated-physiologic loading for 7 and 21 days.


OBJECTIVE
To study the effect of limited nutrition on disc cells embedded in their native tissue in short- and midterm whole organ disc culture.


BACKGROUND
Nutrient-limited induction of disc cell death in vitro has been demonstrated and is believed to be a factor in disc degeneration. Nutrient-limited cell death and its consequences, as it relates to degeneration, have not been investigated in the intact IVD.


METHODS
Ovine IVDs with endplates were cultured for 7 and 21 days under simulated-physiologic loading, either in media with limited (2 g/L) or sufficient (4.5 g/L) glucose concentration. Cell viability, relative gene expression, newly synthesized chondroitin sulfate content, and matrix metalloproteinase (MMP) activity were measured after culture and compared to fresh tissue.


RESULTS
In sufficient glucose media, cell viability was maintained through 7 days to 21 days of culture. In limited glucose, it dropped significantly to 62% in the anulus fibrosus and to 56% in the nucleus pulposus after 7 days and remained so until 21 days (63% in the anulus fibrosus and 52% in the nucleus pulposus). No significant differences were found between culture conditions for relative gene expression, newly synthesized chondroitin sulfate and inactive and active forms of MMP13 and MMP7.


CONCLUSIONS
With this culture system, whole IVD explants could be maintained up to 21 days. Cell viability decreased to 50% to 60% under limited nutrition within days and remained so up to 3 weeks. The surviving cells did not compensate matrix production in this time frame.
Jünger
Svenja
S
AO Research Institute, Davos, Switzerland.
Gantenbein-Ritter
Benjamin
B
Lezuo
Patrick
P
Alini
Mauro
M
Ferguson
Stephen J
SJ
Ito
Keita
K
D000818:Animals; D016923:Cell Death / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D019902:Chondrocytes / Q000378:metabolism* / Q000473:pathology; D002809:Chondroitin Sulfates / Q000096:biosynthesis / Q000235:genetics; D019245:Compressive Strength / Q000502:physiology; D005109:Extracellular Matrix / Q000235:genetics / Q000378:metabolism; D051445:Fibrocartilage / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D015870:Gene Expression / Q000502:physiology; D005947:Glucose / Q000172:deficiency*; D007403:Intervertebral Disc / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D007405:Intervertebral Disc Displacement / Q000209:etiology / Q000378:metabolism* / Q000503:physiopathology; D007511:Ischemia / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology; D020782:Matrix Metalloproteinases / Q000096:biosynthesis / Q000235:genetics; D009924:Organ Culture Techniques / Q000379:methods; D034561:Sheep, Domestic; D016474:Weight-Bearing / Q000502:physiology
D002809:Chondroitin Sulfates; D020782:Matrix Metalloproteinases; D005947:Glucose