| Skin aging is the most common aging phenomena of the human body, its clinical manifestations are skin dry、thinner and wrinkly etc, it directly affects the appearance and health of people, also evokes a series of psychological and social problems. Therefore, prevent and delay skin aging have became one of the hot spots and focuses in present medical research. The pathogenesis of skin aging is unclear now, while the treatment methods and means are still immature, therefore it needs more deeply studies about the molecular mechanism to provide experimental basis for delaying skin aging.Objective:1. To research the effects of water extracts of walnut kernel (WWE) on skin morphological structure、thickness and water content on skin aging mice.2. To explore the influence of WWE on collagenous fiber on skin aging mice.3. Experimental study of WWE on expression of Bax, Bcl-2, Caspase-3on skin aging mice.Method:1. The mouse model of skin aging was established by nape subcutaneous injection of5%D-galactos (D-gal) into the skin combined with ultraviolet (UV) irradiation on the back of mice, and the skin aging mice were given WWE by gavage for consecutive30days. Observe the skin morphological structure change of walnut extracts by visual observation, HE staining, skin thickness and water content detection on skin aging mice.2. The pathological change on collagenous fibers ware examined through Masson staining, the contents of hydroxyproline(Hyp)were measurde by biochemical methods, the expression of matrix metalloproteinases9(MMP9) were assessed by immunohistochemistry and Western Bloting.3. Observe the expression of water extracts of walnut kernel on skin apoptosis related proteins Bax, Bcl-2and Caspase-3to skin aging mice by immunohistochemistry and Western Bloting.Results:1. After the mice of skin aging were established by nape subcutaneous injection of5%D-galactos into the skin combined with UV irradiation on the back of mice for40days, compared with the normal group, the skin of mice in the model group were rough and matt, while the epidermal and dermal boundaries were unclear, even the thickness and water content were also decreased significantly. After the mice were taken in water extracts of walnut kernel for30days, the skin of mice in treatment group were delicate, less wrink, the epidermal and dermal lines were clear, while the thickness of epidermis were significantly increased and the dermal width increased too (P<0.05、P<0.01、P<0.01), the water content raised obviously, and those differences were statistically significant (P<0.05、P<0.05、P<0.01).2. Compared with the normal group, the collagen fibers in the model group were thinner and looser, the contents of Hyp were statistically decreased, but the expression of MMP9were obviously raised. While the collagen fibers in both the middle and high dose of WWE groups were thicker and tighter, the contents of Hyp were statistically increased, whereas the expression of MMP9were significantly decreased.3. Immunohistochemistry and immunofluorescence detection the expressions of Bax, Bcl-2, Caspase-3of skin in skin aging mice:compared with the normal group, the expression of Bax increased significantly in the model group, the positive cell rate of Bcl-2decreased obviously, so that the ratio of Bcl-2/Bax were lower, while the positive cell rate of Caspase-3raised greatly. Compared with the model group, the expression of Bax decreased significantly in the low, middle and high dose of WWE groups, while the positive cell rate of Bcl-2raised obviouslyand, the ratio of Bcl-2/Bax were higher, correspondly the positive cell rate of Caspase-3reduced greatly in all of the groups which were given walnut extracts.4. Western Bloting detection the protein expressions of Bax、Bcl-2、Caspase-3of skin in skin aging mice:compared with the normal group, the OD ratios of Bax /β-actin increased significantly in the model group, the OD ratios of Bcl-2/β-actin decreased obviously, and the OD ratios of Caspase-3/β-actin raised significantly. Compared with the model group, the OD ratios of Bax/β-actin decreased significantly in all of the treatment groups (P<0.05,P<0.05, P<0.01), the OD ratios of Bcl-2/β-actin were significantly higher in the middle and high dose of WWE groups, while the ratios in the low dose of WE groups were only on the increase, and the OD ratios of Bcl-2/Bax increased significantly in the middle and high dose of WE groups, but the ratios in the low dose of WWE groups didn’t change obviously. In addition, compared with the model groups, the OD ratios of Caspase-3/β-actin decreased significantly in all of the treatment groups.Conclusion:1. Nape subcutaneous injection of5%D-galactose into the skin combined with UV irradiation on the back in mice to make the mouse model of skin aging could be scientific and innovative, it was an ideal tool to study skin aging which was caused by metabolic disorders of free radical.2. Water extracts of walnut kernel can protect the collagenous fiber on skin aging mice, and its mechanism may be related to increase the synthesis of Hyp and inhibit the expression of MMP9.3. WWE can inhibit apoptosis by adjusting the expression of Bax, Bcl-2, Caspase-3, etc, and mitigate the damage of skin aging caused by nape subcutaneous injection D-gal combined with UV irradiation. |
PDF Full Text Request