Tryptophan metabolism alters in rotator cuff tear repair in a rat model
10.3760/cma.j.cn115530-20231224-00263
- VernacularTitle:大鼠肩袖撕裂重建过程中色氨酸代谢的变化
- Author:
Dongxu ZHU
1
;
Xiaohong HUANG
;
Xinrui ZHU
;
Tengbo YU
;
Yingze ZHANG
Author Information
1. 青岛大学医学部，青岛 266000
- Keywords:
Tryptophan;
Lacerations;
Osteoporosis;
Rotator cuff tear;
Bone insertion
- From:
Chinese Journal of Orthopaedic Trauma
2024;26(5):435-443
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To explore whether tryptophan metabolism is related to bone growth by comparing the differences in tryptophan metabolism after rotator cuff tear (RCT) repair between rats with normal bone remodeling capability and those with defective bone remodeling capability.Methods:Of the 50 adult female Sprague Dawley (SD) rats used for this study, 18 were randomly selected to undergo bilateral ovariectomy (OVX) (OVX group), and the remaining 32 underwent bilateral OVX sham surgery (sham surgery group). All rats were maintained in standard conditions. Three months after surgery, 4 rats were randomly selected from OVX group and the sham surgery group, respectively, for Micro CT identification of bone loss at the rat humeral head. The remaining rats in OVX group underwent RCT modeling and surgical repair of acute supraspinatus muscle transection (OVX+RCT group) ( n=14); the remaining rats in the sham surgery group were subjected to either surgical repair of acute supraspinatus muscle transection (RCT group, n=14) or RCT sham surgery (SO group, n=14). The grip power of the rats was tested 2 weeks after surgery. The supraspinatus tendon-bone complex was harvested for evaluation of new bone formation and growth through real-time fluorescence quantitative polymerase chain reaction (qPCR), hematoxylin eosin (HE) staining, and immunohistochemistry (IHC) staining. The tryptophan metabolism was analyzed using ultra high performance liquid chromatography (UPLC). Results:The grip power test showed that SO group had the greatest grip power, followed by RCT group and OVX+RCT group, with statistically significant differences between the 3 groups ( P<0.05). The qPCR showed that the relative expression of osteosclerosis in the tendon-bone complex in SO group was significantly higher than that in OVX+RCT group and RCT group; IHC staining showed that the relative expression of osteocalcin in RCT group was significantly higher than that in SO group and OVX+RCT group ( P<0.05). The UPLC showed that the content of tryptophan in the rotator cuff tendon-bone complex was similar among SO, RCT, and OVX+RCT groups, showing no significant difference ( P>0.05). The qPCR showed that the expression of indoleamine 2, 3-dioxygenase 2 in the Kynurenic acid metabolism pathway showed an increasing trend from SO group to RCT group to OVX+RCT group, with OVX+RCT group significantly higher than SO group ( P<0.05). The expression of 3-hydroxybenzoate 3, 4-dioxygenase in OVX+RCT group was significantly higher than that in RCT group and in SO group ( P<0.001). The subtypes A and B of monoamine oxidase in the 5-hydroxytryptamine metabolism pathway increased from SO group to RCT group to OVX+RCT group. The subtypes A and B of monoamine oxidase in the 5-hydroxytryptamine metabolism pathway increased among SO, RCT, and OVX+RCT groups( P<0.001). The expression of dopamine decarboxylase in the indole metabolism pathway in OVX+RCT group was significantly higher than that in SO group ( P<0.01). The expression of cytochrome P450 oxidoreductase increased from SO group to RCT group to OVX+RCT group ( P<0.001). Conclusions:The tryptophan metabolism in the supraspinatus tendon-bone complex after RCT in rats is mainly dominated by kynurenic acid metabolism, followed by 5-hydroxytryptamine metabolism. In RCT bone remodeling, the 5-hydroxytryptamine metabolic pathway changes the most, followed by the indole pathway. The contents of niacin and xanthurenic acid in the kynurenic acid metabolism pathway are related to bone growth; the 5-hydroxytryptamine, hydroxyindoleacetic acid, and melatonin in the 5-hydroxytryptophan metabolic pathway are related to bone growth; the tryptophan and indole lactate in the indole metabolism pathway are related to bone growth. Therefore, tryptophan metabolism is related to bone growth, providing potential therapeutic targets for RCT repair.
