Seasonal climate effect on organ proportion and morbidity in “Bi-zheng” rats with kidney deficiency syndrome

Abstract

Objective: Using the traditional Chinese medicine theory of “Bi-zheng'' caused by kidney deficiency, combined with modern medical science and technology, this study assessed the relationships among organ weight, cytokines, pathological manifestations, and traditional Chinese medicine kidney deficiency syndrome in rats with rheumatoid arthritis. Methods: Sixty Sprague–Dawley rats were randomly divided into normal, collagen-induced arthritis (CIA) model, and kidney deficiency arthralgia model groups. Rats in the kidney deficiency arthritis group underwent removal of the testis or ovary and administration of an inflammatory agent. Rats in the control group solely received an inflammatory agent. Type II collagen-induced arthritis was induced within 1 week of the winter solstice or summer solstice, in order to sample organs and observe the mental state, posture, fur color, activity level, excrement, body weight, and organ weight of the rats. Results: Compared with the normal and CIA model groups, the kidney deficiency arthralgia model group showed fast and acute onset, prominent symptoms, most obvious potential joint swelling, worst general state, and least amount of weight gain. Compared with the normal group, the proportion of thymus, spleen, and adrenal glands of model rats were larger in winter, with varying degrees of hyperplasia and hypertrophy; these differences were statistically significant (P < .05). In summer, model coefficients were greater than normal in the spleen, while the thymus and adrenal gland coefficients were significantly different between the normal and kidney deficiency arthralgia groups. In summer, the thymus in the kidney deficiency arthralgia group exhibited hypertrophy and hyperplasia, whereas the thymus in the control group did not; this difference was statistically significant (P = .015). Thymus and adrenal gland proportions exhibited seasonal differences in CIA model rats; these were statistically significant (P < .05), with high performance in winter and low performance in summer. The spleen proportion exhibited a trend of high performance in winter and low performance in summer in the kidney deficiency arthralgia model rats. Conclusion: Kidney deficiency is an internal condition linked with the occurrence of arthralgia, and seasonal factors exhibit an impact on the morbidity of arthritis in rats. Keywords: Seasonal correlation, Kidney deficiency, Arthralgia, Rats