ABSTRACT
ObjectiveTo evaluate the effects of all-trans retinoic acid(ATRA) on melanin content,activity and protein expression of tyrosinase,mRNA expression of Cu/Zn superoxide dismutase(SOD) in A375 cells irradiated with ultraviolet B(UVB).MethodsCultured A375 cells were classified into 6 groups:ATRA+UVB group treated with ATRA after UVB irradiation,hydroquinone+UVB group treated with hydroquinone after UVB irradiation,UVB group and ATRA group treated with UVB irradiation and ATRA respectively,negative control group receiving no treatment.Melanin content and tyrosinase activity were determined by NaOH solubilization assay and dopa-oxidation assay respectively at 24,48 and 72 hours after the addition of ATRA into medium.Western blot was performed to detect the protein expression of tyrosinase,and real-time quantitative PCR to measure the mRNA expressions of tyrosinase and Cu/Zn SOD in A375 cells after 24-hour culture with ATRA.ResultsThe melanin content and tyrosinase activity decreased in UVB-irradiated cells after being treated with ATRA for 24,48 and 72 hours.The protein (gray scale) and mRNA (2-△△Ct value) expression levels of tyrosinase were 0.72 ± 0.070 and 1.400 ± 0.135 respectively at 24 hours after UVB irradiation,decreased to 0.42 ± 0.056(P ＜0.01) and 0.810 ± 0.062(P ＜ 0.01 ) respectively after additional treatment with ATRA.The mRNA expression level of Cu/Zn SOD was 0.323 ± 0.066 in A375 cells at 24 hours after UVB irradiation,and increased to 0.625 ±0.103 (P ＜ 0.01 ) after additional treatment with ATRA.ConclusionATRA can suppress UVB-induced increase in melanin synthesis and elevate Cu/Zn SOD level in A375 cells,likely through tyrosinase pathway.
ABSTRACT
The advantages and disadvantages of traditional method and "PBL"(Problem-Based Learning) in Basic Medicine education are analyzed.Based on the analysis above,a new method which possesses the advantages and discards the disadvantages is introduced to adapt to the education in Basic Medicine in China and will be applied to the laboratory education.
ABSTRACT
Objective:To generate rabbit-anti B16 melanocyte polyclonal antibodies and study the effect on melanocyte proliferation.Methods:Rabbits was immunized with B16 melanocytes to produce rabbit anti-B16 melanocyte polyclonal antibody(pAb).The titer of the antiserum was then detected using the tube agglutination assay;The antiserum was purified through the G protein affinity chromatograph,and the molecular weight of the purified Ab was identifed through SDS-PAGE.The effect of purified IgG on B16 melanocytes proliferation was detected using MTT assay.Results:The titer of the antiserum reaches 1∶1 280;SDS-PAGE shows that the heavy chain molecular weight of the purified IgG is 66.2 kD;MTT assay shows that the IgG fraction inhibited the proliferation of B16 melanocytes with signifancent difference when compared to none IgG or no purified antiserum.Conclusion:The rabbit anti-B16 melanocytes pAb with high titer is preparated successfully.The purified IgG can inhibit proliferation of B16 melanocytes.It could be useful in studying the effect of this antibody on melanocyte growth and pigment metabolism,it also be useful in studying the pathogenesis of vitiligo.