Chapter 32 Tar - 3
Inhibitory Effects of Shale Oils (Ichthyols) on the Secretion of Chemotactic Leukotrienes From Human Leukocytes and on Leukocyte Migration
By BM Czarnetzki published in the J Invest Dermatol 87: 694-697(1986)
I found another study that examined ichthammol action on LTB4 (leukotriene B4) in detail.
LTB4, released from epidermal cells, is deeply associated with itchiness.
This study reports that ichthammol has effects to inhibit synthesis and the activity of LTB4 in leukocytes.
If it has the same effects for epidermal cells, it may explain anti-itch action of ichthammol.
An appliance called the Boyden Chamber was used for the experiment.
Inhibitory Effects of Shale Oils (Ichthyols) on the Secretion of Chemotactic Leukotrienes From Human Leukocytes and on Leukocyte Migration
By BM Czarnetzki published in the J Invest Dermatol 87: 694-697(1986)
I found another study that examined ichthammol action on LTB4 (leukotriene B4) in detail.
LTB4, released from epidermal cells, is deeply associated with itchiness.
This study reports that ichthammol has effects to inhibit synthesis and the activity of LTB4 in leukocytes.
If it has the same effects for epidermal cells, it may explain anti-itch action of ichthammol.
An appliance called the Boyden Chamber was used for the experiment.
Rectangles in the figure depict the porous filter. The semicircles represent lower chambers under the filter filled with the test liquid (LTB4). Upper chambers on the filter are filled with leukocytes and other cells with migration capability. If the test liquid contains substances with high leukocyte chemotaxis, cells in the upper chambers will migrate through the filter is opening and adhere on the filter underside as shown in the illustration.
Calcium ionophore A 23187 was also used in the experiment. This substance, when added to leukocytes, seems to adhere to the cellular membrane and force calcium ions to flow into leukocytes. As a result, LTB4 and other substances will be released from leukocytes. LTB4 not only causes itchiness but also facilitates leukocyte migration. In vivo, leukocytes call up other leukocytes by releasing LTB4.
Calcium ionophore A 23187 was also used in the experiment. This substance, when added to leukocytes, seems to adhere to the cellular membrane and force calcium ions to flow into leukocytes. As a result, LTB4 and other substances will be released from leukocytes. LTB4 not only causes itchiness but also facilitates leukocyte migration. In vivo, leukocytes call up other leukocytes by releasing LTB4.
The upper table shows the results of an experiment that examined how much (%) PMN migration from the upper chamber would be inhibited by ichthammol with the upper chamber filled with PMN (neutrophil) and the lower chamber filled with LMB (mononuclear cell) or LMB stimulated by ionophore and ichthammol of different concentrations (CF Release). In the combination of PMN and ichthammol, inhibition rate rose in accordance with the concentration increase (55→77→100%). The rightmost column shows the measurements of LTB4 synthesized in the lower chamber, which were taken to see how much LTB4 synthesis was lowered compared to the case with no ichthammol added. Since there is an inconsistency between CF release (55→77→100%) and LTB4 (0→0→100%), there might be another factor, in addition to LTB4 synthesis inhibition, that enables ichthammol to inhibit migration.
The upper graph shows the result of experiment where lower chamber was filled with LTB4- containing liquid and ichthammol of 2 different concentrations (light and dark for 2 different kinds of ichthammol) and the upper chamber was filled with PMN to examine migration capability. It is indicated that ichthammol inhibits LTB4 action in the concentration-dependent manner.
This is probably “another factor” mentioned above and ichthammol inhibits LTB4’s action itself as well as LTB4’s release from leucocytes.
This is probably “another factor” mentioned above and ichthammol inhibits LTB4’s action itself as well as LTB4’s release from leucocytes.
For your information, please look at the upper table that shows the result of an experiment that examined the upper to lower chamber migration capability of PMN with the lower and upper chambers set to different ichthammol concentrations. It can be seen that ichthammol itself is capable of inhibiting leukocyte migration.
In 1986 when this paper was written, it was not unknown yet that LTB4 produced by epidermal cells is highly related with itchiness, and it was not discussed that ichthammol was effective for alleviating itchiness. Currently we can predict that ichthammol may have an arachidonate-dependant and lipoxygenase-driven mechanism to alleviate itchiness via LTB4.
This is a good example that reviewing the past experimental results with the currently available wisdom can bring us new findings.
In 1986 when this paper was written, it was not unknown yet that LTB4 produced by epidermal cells is highly related with itchiness, and it was not discussed that ichthammol was effective for alleviating itchiness. Currently we can predict that ichthammol may have an arachidonate-dependant and lipoxygenase-driven mechanism to alleviate itchiness via LTB4.
This is a good example that reviewing the past experimental results with the currently available wisdom can bring us new findings.