Musk gland seasonal development and musk secretion are regulated by the testis in muskrat (Ondatra zibethicus)

BACKGROUND: The muskrat is a seasonal breeder. Males secrete musk to attract females during the breeding season. The testosterone binding to the androgen receptor (AR) in musk glands of muskrat may play an important role conducting the musk secretion process. METHODS: The musk gland, testis and blood samples of musk rats are collected in both breeding and non-breeding seasons. Some part of the samples are kept in liquid nitrogen for transcriptome analysis and Western blotting test. Some part of the samples are kept in 70% alcohol for histology experiment, blood samples are kept at -20 °C for the serum testosterone measurement experiment. RESULTS: This study demonstrates that the quantity of secreted musk, the volume of the musk glands, the diameter of the gland cells and AR expression are all higher during the breeding season than at other times (p < 0.01). StAR, P450scc and 3ß-HSD expression in the Leydig cells of the testis were also higher during this season, as was serum testosterone. AR was also observed in the gland cells of two other musk-secreting animals, the musk deer and small Indian civet, in their musk glands. These results suggest that the testes and musk glands co-develop seasonally. CONCLUSION: The musk glands' seasonal development and musk secretion are regulated by the testes, and testosterone plays an important role in the seasonal development of musk glands.

Effects of crowding and sex on fecal cortisol levels of captive forest musk deer

BACKGROUND: Restricted space and close contact with conspecifics in captivity may be stressful for musk deer, as they are highly territorial and solitary in the wild. So we tested the effects of crowding on stress of forest musk deer (Moschus berezovskii) in heterosexual groups, using fecal cortisol analysis as a non-invasive method. 32 healthy adults during non-breeding seasons were chose as our experimental objects. Group 1 was defined as higher crowding condition, with 10-15 m²/deer (6 enclosures, 10♀ and 6♂); group 2 was defined as lower crowding condition, with 23-33 m²/deer (6 enclosures, 1010♀ and 6♂). Every enclosure contained 1 male and 3 female. These patterns had been existed for years. RESULTS: The results showed that females in lower crowding condition (217.1 ± 9.5 ug/g) had significantly higher fecal cortisol levels than those in higher crowding condition (177.2 ± 12.1 ug/g). Interestingly, crowding seemed have no effect on male fecal cortisol levels (148.1 ± 9.1 ug/g and 140.5 ± 13.3 ug/g, respectively). At both groups, cortisol was significantly lower in males than in females. CONCLUSIONS: These results showed that chronic crowding may affect stress status of captive forest musk deer. The captive environment should consider the space need for musk deer.

Effects of hypoxia inducible factor-1alpha (HIF-1alpha) on the growth & adhesion in tongue squamous cell carcinoma cells.

BACKGROUND & OBJECTIVES: Hypoxia-inducible factor-1 alpha (HIF-1alpha) is a central transcriptional regulator of hypoxic response. Suppression of HIF-1alpha is important for exploring hypoxia-induced pathophysiological events. This study was carried out to analyze the hypoxia-induced changes of biological characteristics in the human tongue squamous cell carcinoma cell line Tca8113 and evaluate the effects of HIF-1alpha on the phenotype of the tongue squamous cell carcinoma. METHODS: HIF-1alpha gene was silenced with synthesized short interfering ribonucleic acids (siRNA). HIF-1alpha expression was measured on mRNA level by real-time reverse transcription (RT)-PCR and protein level by Western blot and immunofluorescence. The cell cycle and apoptosis of Tca8113 cells were analyzed by FACS. The proliferation and adhesion of Tca8113 cells were determined by MTT colorimetric assay. RESULTS: Tca8113 could survive and showed a more aggressive phenotype under hypoxic condition. Exposure to hypoxia induced a prolonged elevation of HIF-1alpha protein and transfection of siRNA targeting HIF-1alpha (siRNA(HIF-1alpha)) reduced HIF-1alpha synthesis as measured on mRNA and protein level. Under normoxic or hypoxic conditions, treatment of Tca8113 cells with siRNA(HIF-1alpha) induced cell apoptosis and inhibited the growth and adhesion. INTERPRETATION & CONCLUSION: siRNA(HIF-1alpha) could attenuate the tolerance against hypoxia in Tca8113 cells and inhibit their aggressive potential. Interfering with HIF-1alpha pathways by siRNA strategy may provide a therapeutic target for human tongue squamous cell carcinomas.