An experimental model to produce partial thickness burn wound.

Simple burn wound models are always warranted. In view of this a partial thickness reproducible 2 degrees C burn wound has been produced using hot molten wax. This model is simple, convenient, and could be used to monitor wound contraction and epithelization in burn wounds.

Wound healing profiles of ketorolac, metronidazole and tinidazole administered post-surgically.

On dead space wounds, drugs (ketorolac, metronidazole and tinidazole) caused a significant (P < 0.01) decrease in breaking strength, granulation tissue weight and hydroxyproline content in male rats. Both the parameters of excision wound were significantly (P < 0.01) hastened by metronidazole and tinidazole only. Post operative management of wounds with ketorolac (a potent analgesic), metronidazole and tinidazole (for anaerobic infections) may be dealt with the risk of a delay in healing. Both metronidazole and tinidazole promote the epithelization process.

Effect of histamine on wound healing.

Using incision, excision and dead space wound models in rats, a study was conducted on the effect of histamine on wound healing. Exogenous histamine given either ip or locally was without any effect. Semicarbazide as (histamine synthesis inhibitor) suppressed healing process (breaking strength of skin incision wound), decreased breaking strength and hydroxyproline content of granulation tissue and delay in period of epithelization. On the other hand compound 48/80 (a promoter of histamine forming capacity) was found to promote wound healing. Exogenous histamine (topical) reversed the anti-healing effect of semicarbazide on incision and excision wounds.

Effects of antihistamines on wound healing.

Role of antihistamines (H1 and H2 blockers) in wound healing by utilizing incision and dead space wound models in albino rats was investigated. H1 blockers (mepyramine and promethazine) were found to decrease breaking strength of 10 day old dermal incision wounds and collagen content (as hydroxyproline) and breaking strength of granulation tissue harvested over tubular implant. On the other hand H2 blockers (Cimetidine and ranitidine) did not alter the above parameters. The findings that H1 blockers suppress healing implicate H1 receptors in alleged prohealing effect of histamine, and suggest clinical evaluation of these agents for suppression of overhealing states like keloid, adhesions and strictures.

A simple method to quantify maturation of wound collagen.

While investigating the effect of NSAIDs and Zn(II) (NSAIDs)2 complexes on healing of dead space wounds we found that both NSAIDs and Zn(II) (NSAIDs)2 reduced collagen content to a comparable extent yet only NSAIDs reduced breaking strength (BS) of wounds. Since collagen content and maturation are the two important determinants of BS it was obvious that only NSAIDs reduced maturation. A simple method to assess the extent of maturation in available collagen is being reported in the present study. While all NSAIDs significantly reduced the maturation of collagen, Zn(II) (NSAIDs)2 complexes per se did not affect the maturation of collagen of 10-day old. Though, chronologically, granulation tissues obtained from both the treated groups were 10-day old, maturation-wise the age of NSAIDs and Zn(II) (NSAIDs)2 treated granulation was 6 and 12 days respectively.

Comparative evaluation of tolmetin & tolmetin-zinc on wound-repair & inflammation.

In view of the reported healing-suppressant activity of some NSAIDs and absence of this adverse effect in their zinc-complexes, tolmetin (Tol), a recently introduced NSAID and its zinc-complex (Tol-Zn) were compared for their wound healing and antiinflammatory profiles in male albino rats. Tolmetin-zinc (Tol-Zn) significantly reversed (P less than 0.01) the suppressant effect of Tol on gain in breaking strength of skin incisions and dead space wounds (breaking strength, g: for control, Tol and Tol-Zn were: 313 +/- 7, 250 +/- 11, 294 +/- 16 in skin wounds; 244 +/- 7, 137 +/- 18, 195 +/- 16 in dead space wounds). Tol-Zn shared the significant (P less than 0.001) suppressant effect of Tol on granuloma formation (granuloma weight, mg: control - 69 +/- 3, Tol - 36 +/- 3.03, Tol-Zn - 37 +/- 2.75) and its collagen content (total hydroxyproline per tissue, microgram: control - 1955 +/- 55, Tol - 1400 +/- 200, Tol-Zn - 1410 +/- 150). Rat paw edema induced by carrageenin was significantly (P less than 0.001) reduced by Tol as well as Tol-Zn. In the chronic model both the agents suppressed significantly (P less than 0.001) granuloma formation by 50 per cent. Zinc sulphate by itself reduced the rat paw edema by 39 per cent (P less than 0.02) and did not affect the other parameters. Zinc-complex appears to be an improved version of tolmetin as an antiinflammatory agent with no adverse effect on the healing process. Tolmetin-zinc promotes gain in breaking strength, not by increasing the collagen content, but by favouring better maturation of available collagen at the wound site.

Effects of procoagulants on wound healing.

As blood coagulation is a prelude for wound healing, a systemic haemocoagulant (Botropase) and local procoagulants (thrombin and fibrin) were evaluated on physical (wound breaking strength, wound half-closure time and period of epithelization), biochemical (granuloma-hydroxyproline and hexosamine) and histological attributes of healing wounds in albino rats. Botropase prompted all phases of tissue repair. Thrombin delayed wound contraction whereas fibrin had no discernable action. The findings that procoagulants modify healing process has bearing on their surgical use.

Effects of enfenamic acid and its zinc salt on wound-healing.

Dose-matched comparison between zinc-salt of enfenamic acid and the parent compound was carried out in experimentally wounded male albino rats bearing either sutured incision, dead-space or excision wounds. Result showed that enfenamic-acid significantly decreased breaking-strength of incision wounds and this effects was totally reversed by zinc present in enfenamic acid-zinc salt. Both the parent compound and the salt had significant granulation suppressant effect in dead-space wounds. In excision wounds epithelization was enhanced by enfenamic acid only. The wound contraction was not affected by either test compound.