Effect of ALA-PDT on the expressions of MMP-9, MMP-13 and TIMP-1 of hypertrophic scar model in rabbit ears

Objective: To investigate the effect of 5-aminolevulinic(ALA)-photodynamic therapy(PDT) on the expressions of MMP-9, MMP-13 and TIMP-1 of hypertrophic scar model in rabbit ears, and analyze the possible therapeutic mechanisms of ALA-PDT treatment to hypertrophic scars of rabbit ears. Methods: The experimental animals were randomly divided into normal control, negative control, high concentration of ALA-PDT, low concentration of ALA-PDT and PDT groups. The latter three groups received ALA-PDT treatment or PDT treatment once a week for 3 weeks. The specimens of the rabbits were collected respectively 1, 2 and 3 months after treatment to be used for RT-PCR and Western-blot test. Results: 1, 2 and 3 months after PDT treatment, the expressions of MMP-9 and MMP-13(including mRNA and protein) in hypertrophic scar tissues of three treatment groups were significantly higher than those of the negative control group(P<0.01), and the expression of TIMP-1 mRNA and protein of three treatment groups were significantly lower than that of the negative control group(P<0.01). There were also significant differences between high-concentration ALA-PDT treatment group and the low one(P<0.05). Conclusion: ALA-PDT is effective in treating hypertrophic scars of rabbit ears, and its possible therapeutic mechanisms are that ALA-PDT treatment generates oxidation activation effect to activate the activity of MMPs and induces the photoaging of fibroblasts of hypertrophic scar tissues of rabbit ears to inhibit the activity of TIMPs, which causes the up-regulation of MMPs and the down-regulation of TIMPs. Because of this, the degradation of collagen and ECM is accelerated and the formation of scars is suppressed.

Effects of Scopolamine on Blood Vessels in Rabbit Ear after Sympathetic and Sensory Denervation

Objectives To investigatethe effects and involved mechanisms of scopolamine(Scop) on rabbit ear blood vessels. Methods Rabbitear blood vessels were desympathetic and desensoryinnervation with surgical operation. Diameters of dor-sal auricular arterial trunks in vivo were measuredwith a pair of compasses and the ruler in a dissectingmicroscope, and effluents from isolated ear underconstant perfusion pressure were recorded with a digi-tal drop-recorder. Results Intramuscular injectionof Scop 0.1 mg/kg made the diameter of denerveddorsal auricular arterial trunks, as well as that of in-nerved ones, significantly increased. Scop by itself,atthe maximal concentration (Cmax) of 3μM, 30μMand 300μM, did not alter the effluent flow from theisolated denervated rabbit ear, but chlorpromazine(CPZ), at Cmax of 1μM, acetylcholine (ACh), 0.25μM, all significantly increased the effluent flow, andnorepinephrine (NE), 0.1μM, significantly decreasedthe effluent. Scop, 3μM, did not affect ACh (0.25μM)-induced the increase of effluent flow, but Scop,30μM, alleviated the increase. Scop, 3μM, did notaffect NE (0.1μM)-induced the decrease of effluentflow, but Scop, 10, 30 and 100μM, significantly alle-viated the decrease. Conclusions The study sug-gests that Scop has no direct vasodilator effect. Thevasodilator effect of Scop is not due to the blockade ofmuscarinic receptor. However, Scop can dilate bloodvessels contracted by α_1-adrenoceptor activation.

Dynamic changes of autophagy during hypertrophic scar formation and the role of autophagy intervention

Background:The role of autophagy in the formation of hypertrophic scars(HS)remains unclear.This study aimed to explore the role and potential mechanism of autophagy during the development of HS.Methods:RNA and protein expression levels of Beclin-1,p62,and LC3II in normal skin tissues and HS specimens from different patients were examined.Autophagy inducers and inhibitors were used to cure established HS in rabbit ears,and the expression of Beclin-1,p62,and LC3II at the RNA and protein level was determined.Lastly,the effects of autophagy inducers and inhibitors on HS development were analyzed.Results:Compared to normal skin tissues,the expression of LC3II and Beclin-1 was higher(P<0.05),while that of p62 was lower(P<0.05)in HS tissues.In addition,the LC3II/LC3I ratio was increased during HS formation,and the altered expression of the three proteins stabilized after one year.Administration of autophagy inducers enhanced the formation of HS as well as the expression levels of LC3II and Beclin-1 but decreased p62 expression.Meanwhile,administration of autophagy inhibitors increased the expression of LC3II,Beclin-1,and p62,along with reduced HS formation.Conclusion:Autophagic activity increased during HS initiation and subsequent stabilization.In addition,autophagy inhibitors were able to inhibit HS formation by suppressing autophagy,whereas autophagy inducers promoted scar hyperplasia by enhancing autophagy。