ObjectiveTo quantitatively determine the levels of type Ⅰ and type Ⅱ collagen mRNA in the intervertebral disc cartilage endplate of injured animal model, and to clarify the cytological function of intervertebral disc chondrocytes during fibrosis repair after intervertebral disc injury.MethodsForty healthy New Zealand rabbits were randomly divided into fibrosus puncture group, upper cartilage endplate single puncture group, upper and lower cartilage endplate multiple puncture group, and sham group. Two experimental animals were randomly selected from each group on the 2nd day, and the 2nd, 8th, 12th, and 24th week after the animal modeling operation to obtain intervertebral disc specimens. The levels of type Ⅰ collagen and type Ⅱ collagen in cartilage endplate cells of the intervertebral disc were determined by reverse transcriptase polymerase chain reaction (PCR). RNA was extracted from the endplate of the intervertebral disc, and the RNA concentration and the ratio of RNA concentration to protein concentration were determined by nucleic acid analyzer. Reverse transcription was performed by Revertaid M-Mulv reverse transcriptase, type Ⅰ and type Ⅱ collagen primers were designed to establish a PCR reaction system, 2% agarose gel electrophoresis (120 V, 40 min) was prepared by using 0.5×TBE electrophoresis buffer. The amplification results were observed under ultraviolet light, and the gray values of different electrophoresis bands were determined.ResultsThe level of type Ⅰ collagen mRNA in each operation group showed a progressive increase after 8 weeks, and the magnitude of the increase was related to the degree of injury. The level of type Ⅱ collagen mRNA showed a transient increase in the fibrosis puncture group and the upper endplate single-puncture group in the first two weeks after the endplate punctures were completed, and then began to decline progressively; in the multiple puncture group, it showed a downward trend from the beginning of the operation. ConclusionsThe synthesis of type Ⅰ collagen in chondrocytes of the injured nucleus pulposus tissue continues to increase with time, while the synthesis of type Ⅱ collagen begin to decrease progressively after a small increase. The formation and change of type Ⅰ and type Ⅱ collagen in injured intervertebral disc chondrocytes are different from natural degeneration.