Nacre extract prevents scopolamine-induced memory deficits in rodents

Objective: To investigate whether the extract from the nacreous layer of pearl oysters (nacre extract) improves impairments in memory caused by scopolamine administration in rodents. Methods: Nacre extract was prepared from the inner shell layer of pearl oyster. Effects of nacre extract on scopolamine-induced memory impairment were estimated using novel object recognition test, Y-maze test, and Barnes maze test. Effect of nacre extract on mRNA expressions which are genes associated with memory in the hippocampus was investigated using semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) analysis. Results: Administration of nacre extract led to the protection against scopolamine-induced impairments in object recognition, short-term memory, and spatial memory. Treatment with nacre extract reversed the mRNA expression of brain-derived neurotrophic factor (BDNF) and Homer protein homolog 1 (Homer-la) in the hippocampus, which decreased with the treatment of scopolamine. Conclusions: These results suggest that nacre extract has attenuating effects on memory impairments induced by scopolamine through the increase in mRNA expression of BDNF and Homer-1a.

Nacre extract prevents scopolamine-induced memory deficits in rodents

Objective:To investigate whether the extract from the nacreous layer of pearl oysters (nacre extract) improves impairments in memory caused by scopolamine administration in rodents.Methods:Nacre extract was prepared from the inner shell layer of pearl oyster. Effects of nacre extract on scopolamine-induced memory impairment were estimated using novel object recognition test, Y-maze test, and Barnes maze test. Effect of nacre extract on mRNA expressions which are genes associated with memory in the hippocampus was investigated using semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) analysis.Results:Administration of nacre extract led to the protection against scopolamine-induced impairments in object recognition, short-term memory, and spatial memory. Treatment with nacre extract reversed the mRNA expression of brain-derived neurotrophic factor (BDNF) and Homer protein homolog 1 (Homer-la) in the hippocampus, which decreased with the treatment of scopolamine.Conclusions:These results suggest that nacre extract has attenuating effects on memory impairments induced by scopolamine through the increase in mRNA expression of BDNF and Homer-1a.

Crecimiento y mortalidad de la concha nácar Pteria sterna en bancos silvestres de Baja California Sur, México

Growht and mortality of the mollusk Pteria sterna in wild banks of Southern Baja California, Mexico. The Gulf of California nacre shell Pteria sterna is an important marine resource in Mexico, and the main species for "half" and round pearl production in the American continent. Wild spat can only be extracted legally for research or culture activities. This study calculates growth and mortality parameters for wild stocks in the eastern coast of Southern Baja California. Height’s data (353 dorso-ventral measurements) were taken from 1997 to 1999 at Santa Rosalía, Mulegé and Loreto Bay coast. The maximum length was estimated at 130.35 mm (124.22-136.48 mm, p>0.95). The length frequency data were set in a "virtual year". Seasonal von Bertalanffy growth parameters were calculated in the ELEFAN I routine, the values are: L∞ = 156.02 mm, k = 0.48 year-1, t0 = -0.216 years, C = 0.43, WP = 0.73. and t s = 0.5. The growth performance index was Φ’ = 4.068. The total mortality was calculated from length-converted catch curve Z = 3.34 year-1. The length-weight relationship was fixed for the equation W = 0.000756 * L(i)2.7075 (r²= 0.90, n = 233). The growth parameters values in experimental repopulation conditions are quite different, in contrast with the growth estimated in wild stocks oysters. The value of total mortality is similar to the estimations for Pinctada fucata populations from the Red Sea and P. radiata from the Mediterranean Sea. Rev. Biol. Trop. 57 (3): 659-670. Epub 2009 September 30.

La concha nácar Pteria sterna sustenta los perlicultivos en México, y es la base de producción de perlas en el continente Americano. Está bajo protección especial desde 1994, y solo puede capturarse semilla natural para cultivo e investigación. Determinamos su crecimiento y mortalidad en bancos silvestres, registrando la altura de ostras de Santa Rosalía, Mulegé y Bahía de Loreto (1997-99). La longitud máxima estimada fue 130.35 mm (124.22-136.48 mm, P>0.95). Las frecuencias de longitudes se ordenaron en un "año virtual" (Guanco 1991). Los parámetros de crecimiento de von Bertalanffy estimados con el programa ELEFAN I fueron: L∞= 156.02 mm, k=0.48año-1, t0=-0.216 años, C= 0.43 y WP = 0.73; el índice de desempeño de crecimiento fue Φ’ = 4.068. La mortalidad total fue de Z = 3.34 año -1por longitud convertida a curva de captura. La regresión del peso total y la altura tuvo la expresión W = 0.000756 * L(i)2.7075 (r²=0.90, n=233). Mostramos la diferencia entre los parámetros de crecimiento en condiciones de repoblamiento experimental y aquellos de individuos silvestres de P. sterna. El valor de mortalidad total es comparable a aquellos de Pinctada fucata en el mar Rojo o P. radiata en el mar Mediterráneo.

Experimental study on biocompatibility of nacre / 中国矫形外科杂志

[Objective]To study the biocompatibility of nacre on cultured human osteoblasts in vitro.[Method]The iliac bone of human were added with collagenase-trypsin,a lot of osteoblasts were released out.Then the osteoblasts were purified and cultured.Subsequently,the 3rd generation cultured human osteoblasts were inoculated with the extract of three materials:nacre,hydroxyapatite,and rubber.The appearance of osteoblast was observed under the phase contrast microscope.Microstructure of the osteoblast was observed under transmission electron microscope.Additionally,to determine whether these three materials affect cell proliferation,the numbers of BrdU-labeled cells were examined at three groups.MTT assay was tested to observe the viability of human osteoblasts.[Result]Under the phase contrast microscope,the appearance of the osteoblasts in two groups were spindle or triangle like,and black nodes were seen in confluent cell layer 19 days after cultured.The observation of electron microscopy showed that the nucleus of the osteoblasts in two groups were big and round,and there were a large number of mitochondrion and rough endoplasmic reticulum in two groups.Stereological analyses of the numbers of BrdU-labeled cells revealed that females produced more cells than males in the dentate gyrus but not in the subventricular zone.[Conclusion]The nacre have no harmful effect to character of biology of human osteoblasts in vitro.

Research of the degradation of nano-nacre powder and the biocompatibility of the nano-nacre composite artificial bone / 中国矫形外科杂志

[Objective]To study the degradation of nano-nacre powder and the biocompatibility of the composite artificial bone made from this nano-scale powder in vivo.[Method]The nano-nacre powder made through mechanical grinding and the artificial bones made from this powder and PDLLA(poly-D,L-lactide acid) were implanted into the femoral holes and the femoral muscle sacs of rats respectively.Normal micron-nacre powder and the artificial bones made from this powder and PDLLA were implanted as control group,and blank group was set up without implanting anything.X-ray photography was performed immediately and at 2,4 and 8 weeks after operation.The animals were injected with tetracycline for fluorescent mark before being killed.Then,the gross specimens,histological and SEM(scanning electron microscope) observations were performed.[Result]All the observations showed that nano-nacre powder degraded faster than micron-nacre powder,meanwhile,the bone defect recovery was the fastest in this group.Both of the composite artificial bones made from those two kinds of nacre powder had the good connection with the adjacent tissue.[Conclusion]The degradation of nano-nacre powder is faster than that of micron-nacre powder in vivo,and it can promote the growing of new bone.Nano-nacre composite artificial bone also has good biocompatibility.It is a kind of better bioactive degradable material.