According to reference[6], local ligation method, that is ligating left upper mandible second molar with oral orthodontic steel ligature and inserting into free gingiva, taking no damage to junctional epithelium as a principal. Accordingly dental plaque can be greatly accumulated and intramuscular injection of prednisolone acetate can reduced the defense function of immune system in experimental animals, resulting in endocrine disturbance and osteoporosis, thus facilitating periodontal disease occurrence. Rats were involved as experimental animal due to their periodontal tissue structure, histopathology, dental plaque formation and development, multiply and proliferation are close to human being. Pathological changes of periodontal tissues in periodontitis animals, such as bone resorption and destruction, are all similar with periodontitis lesion in human[7]. In this study, intramuscular injection of hormone was given immediately following ligation, animal death rate was shown to be high, which is possible due to great periodontal injury occurred upon ligation and immediately medication of hormone could reduce resistance and result in infective death[8]. Therefore, intramuscular injection of hormone conduced at 2 days after ligation, totally 9 times, then models were confirmed a success through X-ray film and pathological section.
IL-1β and TNF-α, as the cytokines determined in this study, aim to induce inflammation, directly or indirectly mediate bone tissue absorption, their varying biological effects correlate with periodontal tissue destruction, thus considered as an important factor to mediate periodontitis[9-10]. Studies reported that, IL-1 and TNF-α exhibited a high concentration in gingival crevicular fluid of periodontitis sites, and then reduced following treatment[11]; the increased inflammation degree of periodontitis relates with the increased IL-1 concentration[12]; in case of primitive model of chronic periodontitis, IL-1 and TNF-α antagons can reduce the inflammation cells in alveolar bone by 80% and bone absorption by 60%[13]. IL-1 and TNF-α in gingival crevicular fluid can be used as an effective and non-invasive method for periodontitis process determination. Periodontal treatment could reduce the levels of IL-1 and TNF-α[14]. IL-6 influences periodontitis through the following aspects[15]: ①induces vascular endothelial growth factor expression in periodontal tissues, promotes vascularization, aggravates energy expenditure and inflammation; ②inhibits periodontal membrane cells growth, influences tissue metabolism and repair function; ③induces osteoblast to generate osteoclast differentiation factor and matrix metalloproteinase, which can promote bone matrix degradation; ④inhibit osteoblast alkaline phosphatase activity and osteogenesis action. Many scholars report that IL-6 expression in periodontal tissues has a positive correlation with periodontitis degree, IL-6 expression can serve as an indicator of periodontal tissue destruction, effective controlling IL-6 plays an important significance on periodontitis treatment[16].
BGP widely exists in vertebrate bone tissues and is a marker of mature osteoblasts[17-18]. Current evidence indicate that BGP indicative role remains controversial although it is a specific and sensitive biochemical indicator for bone metabolism. McCracken et al[19] have reported serum BGP concentration increases, then alveolar bone exhibited obvious destruction. King et al [20] have studied the bone transition in the process of orthodontic movement through a combined method of histomorphology and serum BGP determination, results showed that serum BGP concentration increased at the peak of bone formation, which was consistent with the present study outcomes. Therefore the increased BGP level is not enough to express bone formation or bone resorption, it is suggested to combine with other determination indices to conduct comprehensive analysis, therefore the levels of TNF-α, BGP, IL-1β, IL-6 were determined simultaneously in this study to obtain a objective outcome.
Berberine hydrochloride, as an active component of traditional Chinese medicine Golden Thread, acts a broad-spectrum antibacterial activity and is usually applied in clinical treatment of intestinal bacteria infection[21-22]. Recent studies have proved anti-arrhythmia, hypoglycemic effect, anti-inflammation and immunoloregulation[23-25]. It has achieved a use in Department of Stomatology to treat recurrent aphtha, periapical periodontitis, radioactive dental membranitis and pericoronitis[26]. In this study, gross observation and histomorphology of the experimental periodontitis rats were shown to improve following berberine hydrochloride treatment, in comparison with model group; the levels of TNF-α, IL-1β, IL-6 in periodontal tissues were significantly decreased, while BGP levels was significantly increased compared with model group (P < 0.05). Indicating the fact that the levels of TNF-α, BGP, IL-1β, IL-6 in periodontal tissues correlates with the periodontitis degree and bone destruction, also berberine hydrochloride can reduce the levels of TNF-α, IL-1β, IL-6 in periodontal tissues and increase BGP level upon inflammation reaction, avoid inflammatory reaction, directly or indirectly inhibit bone resorption, inhibit inflammatory cells aggregation into periodontal tissues, inhibit osteoclast formation, and relieve osteoclast function[27]. It is indicated that berberine hydrochloride can relieve inflammation reaction, inhibit osteoclast formation and promote functional rehabilitation of periodontitis patients in clinical context.
