Establishment and evaluation of a rat model of cervical spondylosis with Yin deficiency syndrome.

Objective: To establish and evaluate a rat model of cervical spondylosis (CS) with yin deficiency syndrome.

Methods: Thirty-six male Sprague-Dawley rats were randomly assigned to the control group, CS group, and CS with Yin deficiency syndrome (YCS) group (n = 12 per group). The control group underwent daily routine care for 37 days. The CS group underwent induction of cervical static-dynamic imbalance, followed by 30 days of standard care. The YCS group underwent cervical static-dynamic imbalance induction, followed by 7 days of sleep deprivation to model Yin deficiency cervical spondylosis. Behavioral performance, heart rate, blood pressure, mechanical pain thresholds, serum cAMP, cGMP, cAMP/cGMP levels, and the expression of collagen-II, Bcl-2, Bax, and Bcl-2/Bax in cervical intervertebral discs were analyzed at various time points.

Results: Following CS induction, modeled rats exhibited significant changes in intervertebral disc structure, including misalignment of the annulus fibrosus, atrophy of the nucleus pulposus, rough cartilaginous endplate boundaries, and disc degeneration. Mechanical pain thresholds decreased. In the YCS group, compared with the CS and control groups, rats showed heightened excitability, dull fur, reddish mouth, lips, nose, paws, and tail, resistance to handling, slower weight gain, initial heart rate elevation followed by decline, and progressive blood pressure reduction. Serum cAMP and cAMP/cGMP ratios were significantly elevated, while cGMP levels were reduced. Collagen-II, Bcl-2, and Bcl-2/Bax levels decreased, and Bax levels increased.

Conclusion: The established rat model of Yin deficiency syndrome aligns with clinical and traditional Chinese medicine characteristics, making it a promising model for studying Yin deficiency syndrome.