Curcumin-activated Wnt5a pathway mediates Ca2+ channel opening to affect myoblast differentiation and skeletal muscle regeneration.

BACKGROUND: Skeletal muscle injury is one of the most common sports injuries; if not properly treated or not effective rehabilitation treatment after injury, it can be transformed into chronic cumulative injury. Curcumin, an herbal ingredient, has been found to promote skeletal muscle injury repair and regeneration. The Wnt5a pathway is related to the expression of myogenic regulatory factors, and Ca2+ promotes the differentiation and fusion process of myoblasts. This study explored the effect and mechanism of curcumin on myoblast differentiation during the repair and regeneration of injured skeletal muscle and its relationship with the Wnt5a pathway and Ca2+ channel. METHODS: Myogenic differentiation of C2C12 cells was induced with 2% horse serum, and a mouse (male, 10 weeks old) model of acute skeletal muscle injury was established using cardiotoxin (20 µL). In addition, we constructed a Wnt5a knockdown C2C12 cell model and a Wnt5a knockout mouse model. Besides, curcumin was added to the cell culture solution (80 mg/L) and fed to the mice (50 mg/kg). Fluorescence microscopy was used to determine the concentration of Ca2+. Western blot and RT-qPCR were used to detect the protein and mRNA levels of Wnt5a, CaN, NFAT2, MyoD, Myf5, Pax7, and Myogenin. The expression levels of MyoD, Myf5, Myogenin, MHC, Desmin, and NFAT2 were detected using immunofluorescence techniques. In addition, MyoD expression was observed using immunohistochemistry, and morphological changes in mouse muscle tissue were observed using HE staining. RESULTS: During myoblast differentiation and muscle regeneration, Wnt5a expression was upregulated (P < 0.001) and the Wnt5a signalling pathway was activated. Wnt5a overexpression promoted the expression of MyoD, Myf5, Myogenin, MHC, and Desmin (P < 0.05), and conversely, knockdown of Wnt5a inhibited their expression (P < 0.001). The Wnt5a pathway mediated the opening of Ca2+ channels, regulated the expression levels of CaN, NFAT2, MyoD, Myf5, Myogenin, MHC, and Desmin (P < 0.01) and promoted the differentiation of C2C12 myoblasts and the repair and regeneration of injured skeletal muscle. The expression of Wnt5a, CaN, NFAT2, MyoD, Myogenin, Myf5, and MHC in C2C12 myoblast was significantly increased after curcumin intervention (P < 0.05); however, their expression decreased significantly after knocking down Wnt5a on the basis of curcumin intervention (P < 0.05). Similarly, in Wnt5a knockout mice, the promotion of muscle regeneration by curcumin was significantly attenuated. CONCLUSIONS: Curcumin can activate the Wnt5a signalling pathway and mediate the opening of Ca2+ channels to accelerate the myogenic differentiation of C2C12 cells and the repair and regeneration of injured skeletal muscle.

[P27Kip1 expression and its prognostic implication in breast carcinoma: a meta-analysis].

OBJECTIVE: To evaluate the relationship between p27Kip1 low expression in breast cancer and its prognostic implication in breast carcinoma patients. Methods All data that were associated with the study of the relationship between p27Kip1 and the prognosis for breast cancer was pooled from Cochrane library, PubMed, Embase and Medlinebase. The outcome was measured using the risk ratio (RR). Data pooling was performed by RevMan 4. 2. Results 6457 patients from 20 studies were included in this meta-analysis. RR estimate of overall survival (OS) for patients with low level p27Kip1 was 2.07 [1.66,2.60] (P<0.01). For disease free survival (DFS), the pooled RR was 1.27 [1.10,1.47] (P<0.05). The combined RR estimate of relapse free survival (RFS) for patients with low level of p27Kip1 was 1.49 [0.92, 2.42] (P >0.05). In patients with lymph node negative breast carcinoma, the combined RR for OS and RFS were 1.98 [1.34,2.91] (P <0.01) and 1.28 [0.45,3.65] (P > 0.05), respectively. Among the patients with lymph node positive breast carcinoma, the combined RR for OS and RFS was 1.92 [1.31, 2.82] (P=0.0009) and 1.35 [0.96,1.89] (P>0.05) respectively. Conclusions Low level of p27Kip1 appears to be an independent prognostic factor to OS and DFS of breast cancer patients but not to RFS. Additional studies with large patient number and widely accepted practical methods are required to derive the precise prognostic significance of p27Kip1 expression in breast cancer patients.

[Dot enzyme-linked immunosorbent assay for detection of serum antibody to Blastocystis hominis in humans].

Serum and stool samples were collected from 322 undergraduate students in medical school. Using stool in vitro cultivation as golden standard, 178 cases were found Blastocystis hominis positive and 144 were negative. Dot-ELISA was used to examine the serum samples with a sensitivity of 92.1% (164/178) and specificity of 97.1% (141/144). This revealed that dot-ELISA can be used for antibody detection against Blastocystis hominis.