Objective To investigate the effect of macrophages on podocytes apoptosis in diabetic nephropathy. Methods Differentiated mouse macrophages (RAW264.7) were exposed to normal glucose, high glucose, then the conditioned media (CM) was collected and considered as NC-CM or HG-CM, respectively. Western blotting and immunofluorescent staining were used to detect the specific markers for M1 macrophages (iNOS) and M2 macrophages (MR). ELISA was used to detect the concentration of TNF-α in the CM. Then normal PRMI 1640 media (control), NC-CM or HG-CM was added to podocytes. In some experiments, ROS inhibitors (Tempo), p38 MAPK inhibitor (SB203580), anti-TNF-α neutralizing antibody, and IgG1 isotype control were respectively added to cells with HG-CM. Besides, recombinant mouse TNF-α alone was applied to incubate podocytes. Podocytes apoptosis was accessed by Annexin V-FITC/PI and Hoechst33342 staining. DCFH-DA staining was used to analyse ROS level. Western blotting was used to detect cleaved casepase-3, p38MAPK, and p-p38MAPK protein. Results Macrophages were activated when exposed to high glucose, displaying pro-inflammatory M1 polarization with higher iNOS and lower MR expression. HG-CM but not NC-CM trigged podocytes apoptosis, up-regulated ROS, cleaved casepase-3 and p-p38MAPK. However, the podocytes apoptosis trigged by HG-CM was abolished by either a ROS inhibitor (Tempo) or a p38 MAPK inhibitor (SB203580). Additionally, TNF-α was increased in the HG-CM. TNF-α protein in macrophage was aslo increased when exposed to high glucose. Anti-TNF-α neutralizing antibody blunted the apoptotic response, excess ROS generation and p-p38 MPAK expression in podocytes induced by HG-CM. Moreover, addition of recombinant TNF-α similarly led to podocytes apoptosis, increased ROS and p38 MPAK expression. Conclusion M1 macrophages activated by high glucose released TNF-α to promote podocytes apoptosis via ROS-p38 MAPK pathway.

Objective To observe the effect of neuregulin-1(NRG-1)on retinal ganglion cells(RGCs)in Zucker Di-abetic Fatty(ZDF)rats and explore the mechanism of NRG-1 in exerting neuroprotective effects on the retina.Methods Twenty-four 8-week-old male ZDF rats(24 eyes)were selected.Diabetic obese rat models were established by feeding a high-fat and high-sugar diet(Purina 5008).After 16 weeks,they were randomly divided into the ZDF group and the NRG-1 group(12 rats in each group).Rats in the NRG-1 group received intravitreal injection of human recombinant NRG-1(once a week for a total of two times),rats in the ZDF group were used as negative controls,and Zucker lean control(ZLC)rats were selected as blank controls(ZCL group).The changes in the number of RGCs in rats of each group were observed by immunofluorescence staining.The protein expressions of NOD-like receptor family pyrin domain containing protein 3(NLRP3),Caspase-1,and Gasdermin D(GSDMD)in the retina of rats in each group were observed by immuno-histochemistry and Western blot.Results After 16 weeks of eating a high-fat diet,compared with the ZLC group,the fasting blood glucose of rats in the ZDF group significantly increased(P＜0.001).The results of immunofluorescence stai-ning showed that the RGCs of rats in the ZLC group were continuously and neatly arranged;compared with the ZLC group,the number of RGCs of rats in the ZDF group significantly decreased(P＜0.001);compared with the ZDF group,the num-ber of RGCs of rats in the NRG-1 group significantly increased(P＜0.01).The immunohistochemical results showed that there were statistically significant differences in the average optical density values of NLRP3,Caspase-1 and GSDMD in the retina of rats in each group(all P＜0.01);compared with the ZLC group,the average optical density values of NLRP3,Caspase-1 and GSDMD in the retina of rats in the ZDF group were higher(all P＜0.01);compared with the ZDF group,the average optical density values of NLRP3,Caspase-1 and GSDMD in the retina of rats in the NRG-1 group significantly de-creased(all P＜0.05).Western blot results showed that there were statistically significant differences in the protein ex-pression levels of Brn3a,NLRP3,Caspase-1 and GSDMD in the retina of rats among all groups(all P＜0.01);compared with the ZLC group,the protein expression of Brn3a significantly decreased,while the protein expressions of NLRP3,Caspase-1 and GSDMD significantly increased in the ZDF group(all P＜0.01);compared with the ZDF group,the protein expression of Brn3a significantly increased,while the protein expressions of NLRP3,Caspase-1 and GSDMD significantly decreased in the NRG-1 group(all P＜0.01).Conclusion After retinal lesions occur in diabetic rats,NLRP3,Caspase-1 and GSDMD are all significantly activated.NRG-1 can reduce the expressions of NLRP3,Caspase-1 and GSDMD,reducing damage to RGCs.

Objective To preliminarily investigate the effects of estradiol on retinal microglia and retinal ganglion cells(RGCs)in rats with glucocorticoid-induced ocular hypertension(OHT).Methods Thirty-six male SD rats(36 eyes)were randomly divided into a control group,an OHT group,and an OHT estradiol-treated group(E2-OHT group),with 12 rats in each group.Among them,the rats in the OHT group and the E2-OHT group were given dexamethasone sodi-um phosphate injection under the conjunctiva,and the rats in the control group were injected with the same volume of ster-ile normal saline.Two weeks after modeling,the rats in the E2-OHT group were treated with estradiol eye drops in addition to subconjunctival injection of dexamethasone sodium phosphate.The eyeballs of all rats were removed 4 weeks after mod-eling.The changes in the number of RGCs and the activation of microglia were observed after immunofluorescence stai-ning,the expression levels of Brn3a and Iba1 proteins in the retina were detected by Western blot,and the relative expres-sion levels of tumor necrosis factor α(TNF-α)and interleukin 1 β(IL-1 β)mRNA were detected by real-time quantitative polymerase chain reaction.Results Among the three groups,the intraocular pressure(IOP)of rats showed no signifi-cant difference before modeling(all P＞0.05),but showed a significant difference at 1 week,2 weeks,3 weeks and 4 weeks after modeling(all P＜0.01).Compared with the control group,the IOP of rats in the OHT group at 1 week,2 weeks,3 weeks and 4 weeks after modeling increased significantly(all P＜0.01).Compared with the OHT group,the IOP of rats in the E2-OHT group showed no significant difference at 1 week and 2 weeks after modeling(both P＞0.05),but decreased significantly at 3 weeks and 4 weeks after modeling(both P＜0.01).The immunofluorescence staining results showed that the retinal microglia of rats in the control group were mainly concentrated in the inner plexiform layer,while the retinal microglia of rats in the OHT group migrated to the ganglion cell layer and had morphological changes(amoebic activation state).The morphology and distribution of rat retinal microglia in the E2-OHT group were basically the same as the retinal staining results of rats in the control group.Compared with the control group,the number of RGCs in the OHT group decreased,the relative expression levels of TNF-α and IL-1β mRNA and Iba1 protein increased,while the expression level of Brn3a protein decreased,and the differences were statistically significant(all P＜0.05).Compared with the OHT group,the rats in the E2-OHT group had an increased number of RGCs,a decreased relative expression level of TNF-α and IL-1 β mRNA and Ibal protein,and an increased expression level of Brn3a protein(all P＜0.05).Conclusion Estradiol can inhibit the activation of microglia,reduce the expression of TNF-α and IL-1β in the retina of rats with OHT,and reduce the damage to RGCs.