Table 1.
Animal group information.
Fig 1.
Signal changes were observed at the second week after the inoculation of the isolated three types strain of C. acnes.
Before the surgery, there were no abnormal signals at T1WI and T2WI. An obvious hypointense signal was observed on T1WI and the hyperintense signal was found on T2WI at the C. acnes-inoculated segment (L5-L6, indicated by a white filled arrow) in Group I and Group II. The hypointense signal changes were also observed on T1WI in the rabbits of Group III, while the signal intensity of T2WI decreased in this group animals. No significant signal changes were observed at the internal control segment of L4-L5 in all groups (indicated by a thin arrow).
Table 2.
Signal intensity (adjusted by cerebrospinal fluid) of endplate region.
Fig 2.
Typical histological images of slices from the three groups of rabbits at eighth weeks after the inoculation.
The intervertebral discs from the TSB-inoculated control segment (L4-L5) had distinct nucleus pulposus and normal arranged annulus fibrosus. The segment of three types of C. acnes inoculated intervertebral discs (L5-L6) was demonstrated as disappearance of nucleus pulposus, endplates fracture (black rectangle), disorganized annulus fibrosus, and partly cartilage proliferation.
Fig 3.
RT-qPCR analysis of MMP13 and MMP1 mRNA expression in endplate chondrocytes cocultured with 2% or 4% supernatant of different phylotypes of C.acnes.
*p < 0.05, **p < 0.01.