Dose-dependent in vitro inhibition of rabbit corneal matrix metalloproteinases by an extract of Pothomorphe umbellata after alkali injury

The in vitro ability of Pothomorphe umbellata ethanolic crude extract to inhibit matrix metalloproteinase (MMP) in normal cornea and in cornea after alkali injury was demonstrated. Corneas of albino rabbits were injured with 1 N NaOH for 20 s. After 48 h the corneas were excised, homogenized and analyzed for MMP-9 (92 kDa), pro-MMP-2 (72 kDa) and MMP-2 (67 kDa) activity by gelatin zymography. The activity was also measured in untreated corneas. After electrophoresis of 20 æg protein, gels were incubated with 50, 100, or 250 µg/mL lyophilized hydroethanolic (1:1) root crude extract of P. umbellata standardized for 4-nerolidylcatechol (7.09 percent). The activity of the enzymes was compared with that of untreated gel. At 48 h after injury, the activity of all MMPs was increased compared with untreated eyes. When the gels were incubated with P. umbellata extract the activity of MMP-2, pro-MMP-2 and MMP-9 decreased in a dose-dependent manner. MMP-9 activity decreased by approximately 50 percent after incubation with 50 µg/mL and was completely abolished at 100 and 250 µg/mL of the extract. After incubation with 50 µg/mL the activity of pro-MMP-2 and MMP-2 also decreased by 50 percent. The activity of pro-MMP-2 was almost completely abolished after incubation with 250 µg/mL of the extract. For MMP-2 the incubation with 100 or 250 µg/mL of the extract of P. umbellata promoted a 10-fold decrease in activity. In conclusion, P. umbellata root crude extract can be useful as an alternative therapy to control MMP activity after corneal injury.

Antioxidant status of dog aqueous humor after extracapsular lens extraction

We determined the antioxidant status of the aqueous humor after extracapsular lens extraction in 14 mongrel dogs weighing about 10 kg. The animals were examined by slit lamp biomicroscopy, applanation tonometry and indirect ophthalmoscopy. One eye was submitted to conventional extracapsular lens extraction and the other was used as control. Samples of aqueous humor were obtained by anterior chamber paracentesis before and at days 1, 2, 3, 7 and 15 after surgery. Total antioxidant status was determined as the capacity of aqueous humor to inhibit free radical generation by 2,2-azobis(2-amidopropane) chlorine. Ascorbic acid concentration was measured by HPLC with UV detection. Protein content was determined with the biuret reagent. Statistical analysis was performed by ANOVA followed by the Tukey-Kramer test. Protein concentration increased from 0.61 to 22 mg/ml 24 h after surgery. These levels were maintained and returned to normal at day 7. Total antioxidant capacity was reduced from 50 to about 30 min until day 3 and at day 7 it was equal to control. Ascorbic acid levels were reduced from 252 to about 110 æM and then returned to control values at day 15. Considering the importance of ascorbic acid concentration in aqueous humor for the maintenance of the antioxidant status of the anterior segment of the eye, the decrease of antioxidant defenses suggests that the surgical procedures promote an oxidative stress condition in the eye.

Antioxidant activity of the microalga Spirulina maxima

Spirulina maxima, which is used as a food additive, is a microalga rich in protein and other essential nutrients. Spirullina contains phenolic acids, tocopherols and Beta-carotene which are known to exhibit antioxidant properties. The aim of the present study was to evaluate the antioxidant capacity of a Spirulina extract. The antioxidant activity of a methanolic extract of Spirulina was determined in vitro and in vivo. The in vitro antioxidant capacity was tested on a brain homogenate incubated with and without the extract at 37 degrees Celsius. The IC(50) (concentration which causes a 50 per cent reduction of oxidation) of the extract in this system was 0.18 mg/ml. The in vivo antioxidant capacity was evaluated in plasma and liver of animals recceiving a daily dose of 5 mg for 2 and 7 weeks Plasma antioxidant capacity was measured in brain homogenate incubated for 1 h at 37 degrees Celsius. The production of oxidized compounds in liver after 2 h of incubation at 37 degrees Celsius was measured in terms of thiobarbituric acid reactant substances (TBARS) in control and experimental groups. Upon treatment, the antioxidant capacity of plasma was 71 per cent for the experimental group and 54 per cent for the control group. Data from liver spontaneous peroxidation studies were not significantly different between groups. The amounts of phenolic acids, alpha-tocopherol and Beta-carotene were determined in Spirulina extracts. The results obtained indicate that Spirulina provides some antioxidant protection for both in vitro and in vitro and vivo systems.

Glaucoma experimental no cäo / Experimental glaucoma in the dog

O glaucoma experimental foi produzido em animais como coelho e macaco na tentativa de explicar os mecanismos da doença. Modelos de glaucoma espontâneo também foram descritos. No presente trabalho a elevaçäo da pressäo intraocular (PIO) foi produzida em 12 cäes por hemácia autóloga fixada em glutaraldeído injetada na câmara anterior do olho esquerdo, sob microscópio cirúrgico. O olho direito foi o controle. Tonometria pelo Schiotz foi realizada a cada 24 horas com o animal em posiçäo sentada. Com intervalos de tempo que variavam de 2 a 20 dias após a injeçäo os animais foram sacrificados, os olhos enucleados e congelados, medidos os diâmetros sagital e transversal e entäo fixados em soluçäo de formol a 10 por cento e os cortes corados pela hematoxilina-eosina para exame histológico. Em todos os animais a PIO foi maior quando comparado com os controles, o mesmo acontecendo com a medida dos diâmetros que foram também maiores. Os achados histológicos foram compatíveis com glaucoma

Atividade das fosfatases acida e alcalina de figado e rim, na intoxicacao experimental pelo hexacloriciclohexano tecnico. / Renal and hepatic acid and alkaline phosphatases activity, during experimental technical hexachlorocyclohexane poisoning

Foi estudada a atividade de fosfatases acida e alcalina de rim e figado de ratos, tratados por 60 e 90 dias com 900 ppm de hexaclorociclohexano tecnico. Verificou-se uma diminuicao de 46% e 32% na atividade da fosfatase alcalina, respectivamente de figado e rim, apos 60 dias de tratamento com hexaclorociclohexano, sendo que apos 90 dias, a diminuicao dessa atividade e de 37% e 40%, em relacao aos controles. Nao se observou na atividade de fosfatose acida de figado e rim