The antidepressant tranylcypromine alters cellular proliferation and migration in the adult goldfish brain.

The goldfish (Carassius auratus) is a widely studied vertebrate model organism for studying cell proliferation in the adult brain, and provide the experimental advantage of growing their body and brain throughout their ∼30-year life time. Cell proliferation occurs in the teleost brain in widespread proliferation zones. Increased cell proliferation in the brain has been linked to the actions of certain antidepressants, including tranylcypromine (TCP), which is used in the treatment of depression. We hypothesized that proliferation zones in the adult goldfish brain can be used to determine the antidepressant effects on cellular proliferation. Here, we report that bromodeoxyuridine (BrdU) labeling over a 24-hr period can be used to rapidly identify the proliferation zones throughout the goldfish brain, including the telencephalon, diencephalon, optic tectal lobes, cerebellum, and facial and vagal lobes. In the first 24 hr of BrdU administration, TCP caused an approximate and significant doubling of labeled cells in the combined brain regions examined, as detected by BrdU immunohistochemistry. TCP caused the greatest increase in cell proliferation in the cerebellum. The normal migratory paths of the proliferating cells within the cerebellum were not affected by TCP treatment. These results indicate that the goldfish provide significant advantages as a vertebrate model for rapidly investigating the effects of antidepressant drugs on cellular proliferation and migration in the normal and injured brain.

Effect of low intensity laser interaction with human skin fibroblast cells using fiber-optic nano-probes.

Over the past forty years, many efforts have been devoted to study low power laser light interactions with biological systems. Some of the investigations were performed in-vitro, on bulk cell populations. Our present work was undertaken to apply specially engineered fiber-optic based nano-probes for the precise delivery of laser light on to a single cell and to observe production of low power laser light induced reactive oxygen species (ROS). A normal human skin fibroblast (NHF) cell line was utilized in this investigation and the cells were irradiated under two different schemes of exposure: (1) an entire NHF cell population within a Petri dish using a fan beam methodology, and (2) through the precise delivery of laser energy on to a single NHF cell using fiber-optic nano-probe. Photobiostimulative studies were conducted through variation of laser intensity, exposure time, and the energy dose of exposure. Laser irradiation induced enhancement in the rate of cell proliferation was observed to be dependent on laser exposure parameters and the method of laser delivery. The total energy dose (fluence) had a greater influence on the enhancement in the rate of cellular proliferation than compared to laser intensity. The enhancement in the growth rate was observed to have a finite life-time of several days after the initial laser exposure. Fluorescent life-time imaging of ROS was performed during the nano-based single cell exposure method. The kinetics of ROS generation was found to depend strongly on the laser fluence and not on the laser intensity.