Organ culture of pig cornea: biochemical analyses of mid-term-stored corneal tissue

Freshly prepared pig corneas were cultured at 22 degrees C in TC 199 medium supplemented with HEPES buffer, antibiotics and 10% sterile pig blood serum. The cultures were maintained in a closed system up to 30 days. The hydration as measured by wet and dry weights increased from 80 to 94% after 2 weeks of storage. Glucose decreased slowly and continuously during the culture time by 0.32 mmol in 30 days. This was equivalent to 11 mumol/day, 0.46 mumol/h and finally 0.264 mumol/h/cm2. Lactate increased in the culture accordingly by 0.34 mumol/h/cm2. In the corneal epithelium of the cultured tissues the glucose levels--normally at about 5 mumol/g--equilibrated with those of the medium during the first 10 days; later the epithelial glucose levels increased up to 20-30 mumol/g. The glycogen content of the epithelium remained constant for the first 10 days of storage. The ATP/ADP ratios in the corneal epithelium initially decreased but later recovered to values of about 12. The pO2 in the culture system decreased from 156 to 120 mm Hg, which is equivalent to an oxygen consumption of 7.41 microliters O2/h/cm2. The CO2 production initiating from a level of 16.6 mm Hg was 4.88 microliters/h/cm2. The data showed that the cornea was viable in this culture system for 30 days.